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I-Hydrogen sulfide (H2S) ineziphumo ezininzi zomzimba nezesifo emzimbeni womntu. I-Sodium hydrosulfide (NaHS) isetyenziswa kakhulu njengesixhobo se-pharmacological ukuvavanya iziphumo ze-H2S kwizilingo zebhayoloji. Nangona ukulahleka kwe-H2S kwizisombululo ze-NaHS kuthatha imizuzu embalwa kuphela, izisombululo ze-NaHS zisetyenziswe njengeekhompawundi zabanikeli be-H2S emanzini okusela kwezinye izifundo zezilwanyana. Olu phononongo luphande ukuba amanzi okusela anoxinzelelo lwe-NaHS lwe-30 μM olulungiselelwe kwiibhotile zempuku/impuku anokuhlala ezinzile ubuncinane iiyure ezili-12-24, njengoko kucetyisiwe ngabanye ababhali. Lungisa isisombululo se-NaHS (30 μM) emanzini okusela uze usithulule ngoko nangoko kwiibhotile zamanzi zempuku/impuku. Iisampulu zaqokelelwa kwincam nangaphakathi kwebhotile yamanzi kwiiyure eziyi-0, 1, 2, 3, 4, 5, 6, 12 kunye nama-24 ukulinganisa umxholo we-sulfide usebenzisa indlela ye-methylene blue. Ukongeza, iimpuku ezingamadoda nezibhinqileyo zifakwe i-NaHS (30 μM) kangangeeveki ezimbini kwaye amanqanaba e-serum sulfide alinganiswa yonke imihla ngeveki yokuqala nasekupheleni kweveki yesibini. Isisombululo se-NaHS kwisampuli esifunyenwe kwincam yebhotile yamanzi sasingazinzanga; sehle nge-72% kunye ne-75% emva kweeyure ezili-12 nezingama-24, ngokwahlukeneyo. Kwiisampuli ezifunyenwe ngaphakathi kweebhotile zamanzi, ukwehla kwe-NaHS kwakungabonakali kwiiyure ezi-2; nangona kunjalo, kwehle nge-47% kunye ne-72% emva kweeyure ezili-12 nezingama-24, ngokwahlukeneyo. Inaliti ye-NaHS ayizange ichaphazele inqanaba le-serum sulfide yeempuku ezingamadoda nezibhinqileyo. Ukuqukumbela, izisombululo ze-NaHS ezilungiselelwe ngamanzi okusela akufuneki zisetyenziselwe ukunikela nge-H2S kuba isisombululo asizinzanga. Le ndlela yokusetyenziswa iya kuveza izilwanyana kwi-NaHS engaqhelekanga kwaye incinci kuneemfuno.
I-Hydrogen sulfide (H2S) ibisetyenziswa njengetyhefu ukusukela ngo-1700; nangona kunjalo, indima yayo enokwenzeka njengemolekyuli ye-biosignaling endogenous yachazwa ngu-Abe noKimura ngo-1996. Kwiminyaka engamashumi amathathu edlulileyo, imisebenzi emininzi ye-H2S kwiinkqubo ezahlukeneyo zabantu iye yacaciswa, nto leyo ekhokelela ekuqondeni ukuba iimolekyuli ze-H2S ezinikelayo zinokuba nezicelo zonyango kunyango okanye kulawulo lwezifo ezithile; bona uChirino et al. ukuze ufumane uphononongo lwakutshanje.
I-Sodium hydrosulfide (NaHS) isetyenziswa kakhulu njengesixhobo se-pharmacological ukuvavanya imiphumo ye-H2S kwiinkcubeko ezininzi zeeseli kunye nezifundo zezilwanyana5,6,7,8. Nangona kunjalo, i-NaHS ayisiyonto ifanelekileyo yokunikela nge-H2S kuba iguqulwa ngokukhawuleza ibe yisisombululo se-H2S/HS-, ingcoliswa lula yi-polysulfides, kwaye inyibilikiswa kwaye inyibilikiswe lula4,9. Kwiimvavanyo ezininzi zebhayoloji, i-NaHS iyanyibilikiswa emanzini, nto leyo ebangela ukuguquguquka okungabonakaliyo kunye nokulahleka kwe-H2S10,11,12, i-oxidation ezenzekelayo ye-H2S11,12,13, kunye ne-photolysis14. I-Sulfide kwisisombululo sokuqala ilahleka ngokukhawuleza ngenxa yokuguquguquka kwe-H2S11. Kwisikhongozeli esivulekileyo, isiqingatha sobomi (t1/2) se-H2S simalunga nemizuzu emi-5, kwaye uxinzelelo lwayo luyancipha malunga ne-13% ngomzuzu10. Nangona ukulahleka kwe-hydrogen sulfide kwizisombululo ze-NaHS kuthatha imizuzu embalwa kuphela, ezinye izifundo zezilwanyana zisebenzise izisombululo ze-NaHS njengomthombo we-hydrogen sulfide emanzini okusela kangangeeveki ezi-1-21, zithatha indawo yesisombululo esine-NaHS rhoqo emva kweeyure ezili-12-24. 15,16,17,18,19,20,21,22,23,24,25,26 Le ndlela ayihambelani nemigaqo yophando lwesayensi, kuba imilinganiselo yamayeza kufuneka isekelwe ekusetyenzisweni kwawo kwezinye iintlobo, ingakumbi abantu.27
Uphando lwangaphambi konyango kwi-biomedicine lujolise ekuphuculeni umgangatho weziphumo zokhathalelo lwezigulane okanye zonyango. Nangona kunjalo, iziphumo zophando oluninzi lwezilwanyana azikaguqulelwa ebantwini28,29,30. Esinye sezizathu zokungaphumeleli kokuguqulela kukunqongophala kwengqwalasela kumgangatho weendlela zophando lwezilwanyana30. Ke ngoko, injongo yolu phononongo yayikukuphanda ukuba izisombululo ze-NaHS ezingama-30 μM ezilungiselelwe kwiibhotile zamanzi eempuku/impuku zinokuhlala zizinzile emanzini okusela iiyure ezili-12-24, njengoko kuthiwe okanye kucetyisiwe kwezinye izifundo.
Zonke iimvavanyo kolu phononongo zenziwe ngokuhambelana nezikhokelo ezipapashiweyo zokhathalelo nokusetyenziswa kwezilwanyana zaselabhoratri e-Iran31. Zonke iingxelo zovavanyo kolu phononongo nazo zilandele izikhokelo ze-ARRIVE32. IKomiti yoBuchule beZiko leSayensi ye-Endocrine, iYunivesithi yeSayensi yezoNyango iShahid Beheshti, ivumile zonke iinkqubo zovavanyo kolu phononongo.
I-Zinc acetate dihydrate (CAS: 5970-45-6) kunye ne-anhydrous ferric chloride (CAS: 7705-08-0) zithengwe kwiBiochem, Chemopahrama (Cosne-sur-Loire, France). I-Sodium hydrosulfide hydrate (CAS: 207683-19-0) kunye ne-N,N-dimethyl-p-phenylenediamine (DMPD) (CAS: 535-47-0) zithengwe kwiSigma-Aldrich (St. Louis, MO, USA). I-Isoflurane ithengwe kwiPiramal (Bethlehem, PA, USA). I-Hydrochloric acid (HCl) ithengwe kwiMerck (Darmstadt, Germany).
Lungisa isisombululo se-NaHS (30 μM) emanzini okusela uze uyithulule ngoko nangoko kwiibhotile zamanzi eempuku/empuku. Olu xinzelelo lukhethwe ngokusekelwe kwiimpapasho ezininzi ezisebenzisa i-NaHS njengomthombo we-H2S; bona icandelo leNgxoxo. I-NaHS yimolekyuli emanzi enokuba namanzi ahlukeneyo okumanzi (oko kukuthi, i-NaHS•xH2O); ngokutsho komenzi, ipesenti ye-NaHS esetyenzisiweyo kuphononongo lwethu yayiyi-70.7% (oko kukuthi, i-NaHS•1.3 H2O), kwaye sithathe eli xabiso kwiibalo zethu, apho sisebenzise ubunzima be-molecular obuyi-56.06 g/mol, obubunzima be-molecular ye-NaHS engenamanzi. Amanzi okumanzisa (abizwa ngokuba ngamanzi okukristala) ziimolekyuli zamanzi ezenza isakhiwo se-crystalline33. Ii-hydrate zineempawu ezahlukeneyo zomzimba kunye ne-thermodynamic xa kuthelekiswa nee-anhydrates34.
Ngaphambi kokongeza i-NaHS emanzini okusela, linganisa i-pH kunye nobushushu besinyibilikisi. Galela isisombululo se-NaHS ngoko nangoko kwibhotile yamanzi yempuku/yempuku ekwikheyiji yesilwanyana. Iisampulu zaqokelelwa kwincam nakwingaphakathi kwebhotile yamanzi kwiiyure eziyi-0, 1, 2, 3, 4, 5, 6, 12, kunye ne-24 ukulinganisa umxholo we-sulfide. Ukulinganiswa kwe-sulfide kwathathwa kwangoko emva kwesampulu nganye. Sifumene iisampulu kwincam yetyhubhu kuba ezinye izifundo zibonise ukuba ubungakanani obuncinci bembobo yetyhubhu yamanzi bunokunciphisa ukufuma kwe-H2S15,19. Le ngxaki ibonakala isebenza nakwisisombululo esikwibhotile. Nangona kunjalo, oku bekungenjalo ngesisombululo esisentanyeni yebhotile yamanzi, esasinezinga eliphezulu lokufuma kwaye sasiyi-autoxidizing; eneneni, izilwanyana zasela la manzi kuqala.
Kusetyenziswe iimpuku eziziinkunzi neziziimazi zeWistar kolu phononongo. Iimpuku zagcinwa kwiikheyiji zepolypropylene (iimpuku ezi-2-3 kwikheyiji nganye) phantsi kweemeko eziqhelekileyo (ubushushu obuyi-21-26 °C, umswakama oyi-32-40%) kunye nokukhanya kweeyure ezili-12 (7 kusasa ukuya kwi-7 pm) kunye neeyure ezili-12 zobumnyama (7 pm ukuya kwi-7 am). Iimpuku zazinokufikelela simahla emanzini empompi kwaye zondliwa nge-standard chow (Khorak Dam Pars Company, eTehran, eIran). Iimpuku ezilingana nobudala (iinyanga ezi-6) eziziimazi (n=10, ubunzima bomzimba: 190–230 g) kunye nenkunzi (n=10, ubunzima bomzimba: 320–370 g) zahlulwe ngokungacwangciswanga zamaqela aphathwe yi-control kunye ne-NaHS (30 μM) (n=5 kwiqela ngalinye). Ukumisela ubungakanani besampulu, sisebenzise indlela ye-KISS (Keep It Simple, Stupid), edibanisa amava angaphambili kunye nohlalutyo lwamandla35. Siqale senza uphando lovavanyo kwiigundane ezi-3 saza safumanisa inqanaba le-sulfide ye-serum ephakathi kunye nokuphambuka okuqhelekileyo (8.1 ± 0.81 μM). Emva koko, sicinga ngamandla angama-80% kwaye sicinga inqanaba lokubaluleka elimacala mabini le-5%, sifumanise ubungakanani besampulu yokuqala (n = 5 ngokusekelwe kuncwadi lwangaphambili) oluhambelana nobungakanani besiphumo esimiselweyo se-2.02 kunye nexabiso elichazwe kwangaphambili elicetyiswe yiFesting yokubala ubungakanani besampulu yezilwanyana zovavanyo35. Emva kokuphinda-phinda eli xabiso nge-SD (2.02 × 0.81), ubungakanani besiphumo esibonakalayo esiqikelelweyo (1.6 μM) yayiyi-20%, nto leyo eyamkelekileyo. Oku kuthetha ukuba i-n = 5/iqela yanele ukubona utshintsho oluphakathi lwe-20% phakathi kwamaqela. Iigundane zahlulwe ngokungacwangciswanga zaba ngamaqela alawulwayo kunye naphethwe yi-NaSH kusetyenziswa umsebenzi ongacwangciswanga wesoftware ye-Excel 36 (Umfanekiso Ongezelelweyo 1). Ukufiphaza kwenziwa kwinqanaba lesiphumo, kwaye abaphandi abenza umlinganiselo we-biochemical babengazi ngezabelo zeqela.
Amaqela e-NaHS azo zombini izini anyangwa ngesisombululo se-NaHS se-30 μM esilungiselelwe emanzini okusela kangangeeveki ezi-2; Isisombululo esitsha sanikwa rhoqo emva kweeyure ezingama-24, apho ubunzima bomzimba babulinganiswa khona. Iisampuli zegazi zaqokelelwa kwiincam zomsila wazo zonke iimpuku phantsi kwe-isoflurane anesthesia yonke imihla ekupheleni kweveki yokuqala neyesibini. Iisampuli zegazi zafakwa kwi-centrifuge kwi-3000 g imizuzu eli-10, i-serum yahlulwa yaza yagcinwa kwi--80°C ukuze kulinganiswe i-serum urea, i-creatinine (Cr), kunye ne-total sulfide. I-serum urea yamiselwa ngendlela ye-enzyme urea, kwaye i-serum creatinine yamiselwa ngendlela ye-photometric Jaffe kusetyenziswa iikiti ezithengiswayo (Man Company, Tehran, Iran) kunye ne-automatic analyzer (Selectra E, inombolo ye-serial 0-2124, The Netherlands). Ii-coefficients ze-intra- kunye ne-interassay zokwahluka kwe-urea kunye ne-Cr zazingaphantsi kwe-2.5%.
Indlela ye-methylene blue (MB) isetyenziselwa ukulinganisa i-sulfide iyonke emanzini okusela kunye ne-serum equlethe i-NaHS; i-MB yeyona ndlela isetyenziswa kakhulu ukulinganisa i-sulfide kwizisombululo ezininzi kunye neesampuli zebhayoloji11,37. Indlela ye-MB ingasetyenziselwa ukuqikelela i-sulfide pool iyonke38 kunye nokulinganisa i-sulfides ezingaphiliyo ngendlela ye-H2S, HS- kunye ne-S2 kwi-aqueous phase39. Kule ndlela, i-sulfur ifakwa njenge-zinc sulfide (ZnS) xa kukho i-zinc acetate11,38. I-Zinc acetate precipitation yeyona ndlela isetyenziswa kakhulu yokwahlula i-sulfides kwezinye ii-chromophores11. I-ZnS yaphinda yanyibilika kusetyenziswa i-HCl11 phantsi kweemeko ze-asidi enamandla. I-sulfide isabela ne-DMPD kwi-stoichiometric ratio ye-1:2 kwi-reaction eqhutywa yi-ferric chloride (i-Fe3+ isebenza njenge-oxidizing agent) ukwenza i-dye MB, efunyanwa nge-spectrophotometrically kwi-670 nm40,41. Umda wokufumanisa indlela ye-MB umalunga ne-1 μM11.
Kolu phononongo, i-100 μL yesampulu nganye (isisombululo okanye i-serum) yongezwa kwityhubhu; emva koko i-200 μL ye-zinc acetate (1% w/v emanzini acocekileyo), i-100 μL ye-DMPD (20 mM kwi-7.2 M HCl), kunye ne-133 μL ye-FeCl3 (30 mM kwi-1.2 M HCl) zongezwa. Umxube wafakwa kwi-37°C ebumnyameni imizuzu engama-30. Isisombululo safakwa kwi-centrifuge kwi-10,000 g imizuzu eli-10, kwaye ukufunxwa kwe-supernatant kwafundwa kwi-670 nm kusetyenziswa i-microplate reader (BioTek, MQX2000R2, Winooski, VT, USA). Amanqanaba e-sulfide amiselwe kusetyenziswa i-calibration curve ye-NaHS (0–100 μM) kwi-ddH2O (Umfanekiso oNcedisayo 2). Zonke izisombululo ezisetyenziselwe ukulinganisa zalungiswa ngokutsha. Ii-coefficients zangaphakathi kunye ne-interassay zokwahluka kokulinganiswa kwe-sulfide yayiyi-2.8% kunye ne-3.4%, ngokwahlukeneyo. Sikwafumanise i-sulfide iyonke efunyenwe emanzini okusela kunye neesampuli ze-serum ezine-sodium thiosulfate sisebenzisa indlela yesampuli eqinisiweyo42. Ukufunyanwa kwamanzi okusela kunye neesampuli ze-serum ezine-sodium thiosulfate kwakuyi-91 ± 1.1% (n = 6) kunye ne-93 ± 2.4% (n = 6), ngokwahlukeneyo.
Uhlalutyo lwezibalo lwenziwe kusetyenziswa isoftware yeGraphPad Prism version 8.0.2 yeWindows (GraphPad Software, San Diego, CA, USA, www.graphpad.com). Uvavanyo lwe-t oludibeneyo lusetyenzisiwe ukuthelekisa ubushushu kunye ne-pH yamanzi okusela ngaphambi nasemva kokongezwa kwe-NaHS. Ukulahleka kwe-H2S kwisisombululo esine-NaHS kubalwe njengokuncipha kwepesenti ukusuka ekuthathweni kwesiseko, kwaye ukuvavanya ukuba ilahleko ibalulekile ngokwezibalo, senze i-ANOVA ephindaphindwayo yendlela enye elandelwa luvavanyo lokuthelekisa oluninzi lukaDunnett. Ubunzima bomzimba, i-serum urea, i-serum creatinine, kunye ne-serum sulfide iyonke ngokuhamba kwexesha zithelekiswe phakathi kweempuku eziphathwayo kunye ne-NaHS zesini ezahlukeneyo kusetyenziswa i-ANOVA exutywe ngeendlela ezimbini (phakathi-ngaphakathi) elandelwa luvavanyo lweBonferroni post hoc. Amaxabiso e-P anemisila emibini < 0.05 athathwa njengabalulekileyo ngokwezibalo.
I-pH yamanzi okusela yayiyi-7.60 ± 0.01 ngaphambi kokongezwa kwe-NaHS kunye ne-7.71 ± 0.03 emva kokongezwa kwe-NaHS (n = 13, p = 0.0029). Ubushushu bamanzi okusela babuyi-26.5 ± 0.2 kwaye behla baya kwi-26.2 ± 0.2 emva kokongezwa kwe-NaHS (n = 13, p = 0.0128). Lungisa isisombululo se-30 μM NaHS emanzini okusela kwaye usigcine kwibhotile yamanzi. Isisombululo se-NaHS asizinzanga kwaye uxinzelelo lwaso luyehla ngokuhamba kwexesha. Xa kuthathwa isampuli entanyeni yebhotile yamanzi, kwabonwa ukwehla okukhulu (68.0%) kwiyure yokuqala, kwaye umxholo we-NaHS kwisisombululo wehla nge-72% kunye ne-75% emva kweeyure ezili-12 kunye ne-24, ngokwahlukeneyo. Kwiisampuli ezifunyenwe kwiibhotile zamanzi, ukwehla kwe-NaHS bekungabalulekanga ukuya kuthi ga kwiiyure ezi-2, kodwa emva kweeyure ezili-12 kunye ne-24 kwehle nge-47% kunye ne-72%, ngokwahlukeneyo. Ezi datha zibonisa ukuba ipesenti ye-NaHS kwisisombululo se-30 μM esilungiselelwe emanzini okusela yehlile yaya kuthi ga kwikota yexabiso lokuqala emva kweeyure ezingama-24, nokuba indawo yesampulu ikweyiphi na (Umfanekiso 1).
Uzinzo lwesisombululo se-NaHS (30 μM) emanzini okusela kwiibhotile zeempuku/zeempuku. Emva kokulungiswa kwesisombululo, iisampulu zithathwe kwincam kunye nangaphakathi kwebhotile yamanzi. Idatha iboniswa njenge-avareji ± SD (n = 6/iqela). * kunye ne-#, P < 0.05 xa kuthelekiswa nexesha 0. Umfanekiso webhotile yamanzi ubonisa incam (enokuvulwa) kunye nomzimba webhotile. Umthamo wencam umalunga ne-740 μL.
Uxinzelelo lweNaHS kwisisombululo esisandula ukulungiswa se-30 μM yayiyi-30.3 ± 0.4 μM (uluhlu: 28.7–31.9 μM, n = 12). Nangona kunjalo, emva kweeyure ezingama-24, uxinzelelo lweNaHS lwehla lwaya kwixabiso eliphantsi (umyinge: 3.0 ± 0.6 μM). Njengoko kubonisiwe kuMfanekiso 2, uxinzelelo lweNaHS apho iimpuku zazichatshazelwe khona lwalungaguquki ngexesha lesifundo.
Ubunzima bomzimba weempuku eziziimazi bunyuke kakhulu ngokuhamba kwexesha (ukusuka kwi-205.2 ± 5.2 g ukuya kwi-213.8 ± 7.0 g kwiqela lolawulo kwaye ukusuka kwi-204.0 ± 8.6 g ukuya kwi-211.8 ± 7.5 g kwiqela eliphathwe yi-NaHS); nangona kunjalo, unyango lwe-NaHS aluzange lube nefuthe kubunzima bomzimba (Umzobo 3). Ubunzima bomzimba weempuku eziziinkunzi bunyuke kakhulu ngokuhamba kwexesha (ukusuka kwi-338.6 ± 8.3 g ukuya kwi-352.4 ± 6.0 g kwiqela lolawulo kwaye ukusuka kwi-352.4 ± 5.9 g ukuya kwi-363.2 ± 4.3 g kwiqela eliphathwe yi-NaHS); nangona kunjalo, unyango lwe-NaHS aluzange lube nefuthe kubunzima bomzimba (Umzobo 3).
Utshintsho kubunzima bomzimba kwiimpuku eziziimazi neziziinkunzi emva kokunikwa i-NaHS (30 μM). Idatha iboniswa njenge-± SEM ephakathi kwaye ithelekiswe kusetyenziswa uhlalutyo oluxutywe ngeendlela ezimbini (ngaphakathi) lokwahluka ngovavanyo lweBonferroni emva kwe-hoc. n = 5 yesini ngasinye kwiqela ngalinye.
Amanqanaba e-serum urea kunye ne-creatine phosphate ayefana ekulawuleni kunye neempuku eziphathwe nge-NaSH kulo lonke uphando. Ngaphezu koko, unyango lwe-NaSH aluzange luchaphazele amanqanaba e-serum urea kunye ne-creatinechrome (Itheyibhile 1).
Amanqanaba esiseko e-serum total sulfide ayethelekiswa phakathi kweempuku ezilawulwayo neziphathwe yi-NaHS (8.1 ± 0.5 μM vs. 9.3 ± 0.2 μM) kunye neempuku ezibhinqileyo (9.1 ± 1.0 μM vs. 6.1 ± 1.1 μM). Ulawulo lwe-NaHS kangangeentsuku ezili-14 aluzange lube nefuthe kumanqanaba e-serum total sulfide kwiimpuku ezingamadoda okanye ezibhinqileyo (Umzobo 4).
Utshintsho kumanqanaba e-serum total sulfide kwiimpuku ezingamadoda nezibhinqileyo emva kokunikwa i-NaHS (30 μM). Idatha iboniswa njenge-mean ± SEM kwaye ithelekiswe kusetyenziswa uhlalutyo oluxutywe ngeendlela ezimbini (ngaphakathi-ngaphakathi) lokwahluka ngovavanyo lwe-Bonferroni post hoc. Isini ngasinye, n = 5/iqela.
Isigqibo esiphambili solu phononongo kukuba amanzi okusela ane-NaHS akazinzile: malunga nekota kuphela yomxholo wokuqala we-sulfide onokufunyanwa kwiiyure ezingama-24 emva kokuthatha isampuli ukusuka encamini nangaphakathi kweebhotile zamanzi eempuku/zeempuku. Ngaphezu koko, iimpuku zavezwa kumanqanaba e-NaHS angazinzile ngenxa yokulahleka kwe-H2S kwisisombululo se-NaHS, kwaye ukongezwa kwe-NaHS emanzini okusela akuzange kuchaphazele ubunzima bomzimba, i-serum urea kunye ne-creatine chromium, okanye i-serum sulfide iyonke.
Kolu phononongo, izinga lokulahleka kwe-H2S kwizisombululo ze-NaHS ezingama-30 μM ezilungiselelwe emanzini okusela lalimalunga ne-3% ngeyure. Kwisisombululo esifakwe i-buffered (100 μM sodium sulfide kwi-10 mM PBS, pH 7.4), uxinaniso lwe-sulfide luxelwe ukuba lwehla nge-7% ngokuhamba kwexesha ngaphezulu kweeyure ezi-8. Ngaphambili besikhusele ukuphathwa kwe-NaHS ngaphakathi kwesisu ngokuxela ukuba izinga lokulahleka kwe-sulfide kwisisombululo se-NaHS ezingama-54 μM emanzini okusela lalimalunga ne-2.3% ngeyure (4%/iyure kwiiyure ezili-12 zokuqala kunye ne-1.4%/iyure kwiiyure ezili-12 zokugqibela emva kokulungiswa)8. Izifundo zangaphambili43 zifumene ukulahleka okuqhubekayo kwe-H2S kwizisombululo ze-NaHS, ngokuyintloko ngenxa yokuguquguquka kunye nokuxinana. Nokuba ngaphandle kokongezwa kwamaqamza, i-sulfide kwisisombululo sesitokhwe ilahleka ngokukhawuleza ngenxa yokuguquguquka kwe-H2S11. Izifundo zibonise ukuba ngexesha lenkqubo yokunyibilikisa, ethatha malunga nemizuzwana engama-30-60, malunga ne-5-10% ye-H2S iyalahleka ngenxa yokufuma6. Ukuthintela ukufuma kwe-H2S kwisisombululo, abaphandi bathathe amanyathelo aliqela, kuquka ukuxukuxa kancinci kwesisombululo12, ukugubungela isisombululo sesitokhwe ngeplastiki6, kunye nokunciphisa ukuvezwa kwesisombululo emoyeni, kuba izinga lokufuma kwe-H2S lixhomekeke kujongano lomoya nolwelo.13 Ukufunxwa okuzenzekelayo kwe-H2S kwenzeka ikakhulu ngenxa yee-ion zesinyithi eziguqukayo, ngakumbi i-ferric iron, ezingcoliseko emanzini.13 Ukufunxwa kwe-H2S kuphumela ekwakhiweni kwee-polysulfides (ii-athomu zesulfure ezidityaniswe ziibhondi ze-covalent)11. Ukuze kuthintelwe i-oxidation yayo, izisombululo ezine-H2S zilungiswa kwizinyibilikisi ezingabinayo ioksijini44,45 zize emva koko zicocwe nge-argon okanye i-nitrogen imizuzu engama-20-30 ukuqinisekisa i-deoxygenation.11,12,37,44,45,46 I-Diethylenetriaminepentaacetic acid (DTPA) yi-metal chelator (10-4 M) ethintela i-HS-autoxidation kwizisombululo ze-aerobic. Ukuba ingekho i-DTPA, izinga le-autoxidation ye-HS- limalunga nama-50% ngaphezulu kweeyure ezi-3 kwi-25°C37,47. Ngaphezu koko, ekubeni i-oxidation ye-1e-sulfide ishukunyiswa kukukhanya kwe-ultraviolet, isisombululo kufuneka sigcinwe kwiqhwa kwaye sikhuselwe ekukhanyeni11.
Njengoko kubonisiwe kuMfanekiso 5, i-NaHS iyahlukana ibe yi-Na+ kunye ne-HS-6 xa inyibilikisiwe emanzini; olu qhekeko lumiselwa yi-pK1 yempendulo, exhomekeke kubushushu: pK1 = 3.122 + 1132/T, apho i-T iphakathi kwe-5 ukuya kwi-30°C kwaye ilinganiswa ngamadigri eKelvin (K), K = °C + 273.1548. I-HS- ine-pK2 ephezulu (pK2 = 19), ngoko ke kwi-pH < 96.49, i-S2- ayenziwanga okanye yenziwe ngamanani amancinci kakhulu. Ngokwahlukileyo koko, i-HS- isebenza njengesiseko kwaye yamkela i-H+ kwi-molecule ye-H2O, kwaye i-H2O isebenza njenge-asidi kwaye iguqulwa ibe yi-H2S kunye ne-OH-.
Ukwenziwa kwegesi ye-H2S enyibilikisiweyo kwisisombululo se-NaHS (30 µM). aq, isisombululo samanzi; g, igesi; l, ulwelo. Zonke izibalo zicinga ukuba i-pH yamanzi = 7.0 kwaye ubushushu bamanzi = 20 °C. Yenziwe ngeBioRender.com.
Nangona kukho ubungqina bokuba izisombululo zeNaHS azizinzanga, izifundo ezininzi zezilwanyana zisebenzise izisombululo zeNaHS emanzini okusela njengekhompawundi ye-H2S15,16,17,18,19,20,21,22,23,24,25,26 kunye nobude bokungenelela obuqala kwiiveki ezi-1 ukuya kwezingama-21 (Itheyibhile 2). Ngexesha lezi zifundo, isisombululo seNaHS sasihlaziywa rhoqo emva kweeyure ezili-12, 15, 17, 18, 24, 25 okanye iiyure ezingama-24, 19, 20, 21, 22, 23. Iziphumo zethu zibonise ukuba iimpuku zazichatshazelwe kumanqanaba angazinzanga eziyobisi ngenxa yokulahleka kwe-H2S kwisisombululo seNaHS, kwaye umxholo weNaHS emanzini okusela eempuku utshintshe kakhulu kwiiyure ezili-12 okanye ezingama-24 (jonga uMfanekiso 2). Ezimbini kwezi zifundo zibike ukuba amanqanaba e-H2S emanzini ahlala ezinzile kwisithuba seeyure ezingama-24, okanye ukuba yi-2–3% kuphela yokulahleka kwe-H2S okubonwe kwisithuba seeyure ezili-12, kodwa azizange zibonelele ngedatha exhasayo okanye iinkcukacha zokulinganisa. Izifundo ezimbini zibonise ukuba ububanzi obuncinci beebhotile zamanzi bunokunciphisa ukufuma kwe-H2S15,19. Nangona kunjalo, iziphumo zethu zibonise ukuba oku kunokulibazisa kuphela ukulahleka kwe-H2S kwibhotile yamanzi ngeeyure ezi-2 endaweni yeeyure ezili-12–24. Zombini ezi zifundo ziphawula ukuba sicinga ukuba inqanaba le-NaHS emanzini okusela alitshintshanga kuba asibonanga utshintsho lombala emanzini; ngoko ke, i-oxidation ye-H2S ngumoya yayingabalulekanga19,20. Okumangalisayo kukuba, le ndlela yokujonga izinto ivavanya uzinzo lwe-NaHS emanzini endaweni yokulinganisa utshintsho kuxinzelelo lwayo ngokuhamba kwexesha.
Ukulahleka kwe-H2S kwisisombululo se-NaHS kunxulumene ne-pH kunye nobushushu. Njengoko kuphawuliwe kwisifundo sethu, ukunyibilika kwe-NaHS emanzini kubangela ukwakheka kwesisombululo se-alkaline50. Xa i-NaHS inyibilika emanzini, ukwakheka kwegesi ye-H2S enyibilikisiweyo kuxhomekeke kwixabiso le-pH6. Okukhona i-pH yesisombululo iphantsi, kokukhona inani le-NaHS elikhoyo njengeemolekyuli zegesi ze-H2S liphezulu kwaye i-sulfide eninzi ilahleka kwisisombululo samanzi11. Akukho nanye kwezi zifundo ebike i-pH yamanzi okusela asetyenziswa njengesinyibilikisi se-NaHS. Ngokweengcebiso ze-WHO, ezamkelwe ngamazwe amaninzi, i-pH yamanzi okusela kufuneka ibe kuluhlu lwe-6.5–8.551. Kolu luhlu lwe-pH, izinga le-oxidation ye-spontaneous ye-H2S liyanda malunga neshumi eliphindwe kalishumi13. Ukunyibilika kwe-NaHS emanzini kolu luhlu lwe-pH kuya kubangela uxinzelelo lwegesi ye-H2S enyibilikisiweyo oluyi-1 ukuya kwi-22.5 μM, egxininisa ukubaluleka kokujonga i-pH yamanzi ngaphambi kokunyibilika i-NaHS. Ukongeza, uluhlu lwamaqondo obushushu oluchazwe kuphononongo olungentla (18–26 °C) luya kubangela utshintsho kuxinzelelo lwegesi ye-H2S enyibilikisiweyo kwisisombululo esimalunga ne-10%, kuba utshintsho lwamaqondo obushushu lutshintsha i-pK1, kwaye utshintsho oluncinci kwi-pK1 lunokuba nefuthe elikhulu kuxinzelelo lwegesi ye-H2S enyibilikisiweyo48. Ukongeza, ixesha elide lezinye izifundo (iinyanga ezi-5)22, apho kulindeleke ukuba utshintsho olukhulu kumaqondo obushushu, nalo luyayenza mandundu le ngxaki.
Zonke izifundo ngaphandle kwesinye21 zisebenzise isisombululo se-30 μM NaHS emanzini okusela. Ukuchaza idosi esetyenzisiweyo (oko kukuthi, i-30 μM), abanye ababhali babonise ukuba i-NaHS kwisigaba samanzi ivelisa uxinaniso olufanayo lwegesi ye-H2S kwaye uluhlu lwe-physiological lwe-H2S luyi-10 ukuya kwi-100 μM, ngoko ke le dosi ingaphakathi koluhlu lwe-physiological15,16. Abanye bachaze ukuba i-30 μM NaHS inokugcina inqanaba le-plasma H2S ngaphakathi koluhlu lwe-physiological, oko kukuthi, i-5–300 μM19,20. Sicinga ngoxinaniso lwe-NaHS emanzini angama-30 μM (pH = 7.0, T = 20 °C), olusetyenziswe kwezinye izifundo ukufunda iziphumo ze-H2S. Singabala ukuba uxinaniso lwegesi ye-H2S enyibilikisiweyo yi-14.7 μM, emalunga ne-50% yoxinaniso lokuqala lwe-NaHS. Eli xabiso lifana nexabiso elibalwe ngabanye ababhali phantsi kweemeko ezifanayo13,48.
Kwisifundo sethu, ukulawulwa kwe-NaHS akuzange kutshintshe ubunzima bomzimba; esi siphumo sihambelana neziphumo zezinye izifundo kwiimpuku ezingamadoda22,23 kunye neempuku ezingamadoda18; Nangona kunjalo, izifundo ezimbini zibike ukuba i-NaSH ibuyisele ubunzima bomzimba obunciphileyo kwiimpuku ezifakwe i-nephrectomized24,26, ngelixa ezinye izifundo zingakhange zibike impembelelo yokulawulwa kwe-NaSH kubunzima bomzimba15,16,17,19,20,21,25. Ngaphezu koko, kwisifundo sethu, ukulawulwa kwe-NaSH akuzange kuchaphazele amanqanaba e-serum urea kunye ne-creatine chromium, okuhambelana neziphumo zenye ingxelo25.
Olu phononongo lufumanise ukuba ukongezwa kwe-NaHS emanzini okusela kangangeeveki ezi-2 akuzange kuyichaphazele i-serum sulfide concentrations iyonke kwiimpuku ezingamadoda neziziimazi. Olu phando luhambelana neziphumo zikaSen et al. (16): Iiveki ezi-8 zonyango nge-30 μM NaHS emanzini okusela azizange zichaphazele amanqanaba e-plasma sulfide kwiimpuku ezilawulayo; nangona kunjalo, baxele ukuba olu ngenelelo lubuyisele amanqanaba e-H2S anciphileyo kwi-plasma yeempuku ezifakwe i-nephrectomized. ULi et al. (22) baxele nokuba unyango nge-30 μM NaHS emanzini okusela kangangeenyanga ezi-5 lonyuse amanqanaba e-plasma free sulfide kwiimpuku ezindala malunga ne-26%. Ezinye izifundo azizange zibike utshintsho kwi-circulating sulfide emva kokongezwa kwe-NaHS emanzini okusela.
Izifundo ezisixhenxe zibike kusetyenziswa iSigma NaHS15,16,19,20,21,22,23 kodwa azizange zinike iinkcukacha ezithe vetshe ngamanzi okufunxa, kwaye izifundo ezintlanu azikhankanyanga umthombo weNaHS osetyenzisiweyo kwiindlela zazo zokulungiselela17,18,24,25,26. I-NaHS yimolekyuli emanzi kwaye umxholo wayo wamanzi okufunxa unokwahluka, nto leyo echaphazela ubungakanani beNaHS efunekayo ukulungiselela isisombululo se-molarity ethile. Umzekelo, umxholo weNaHS kwisifundo sethu yayiyiNaHS•1.3 H2O. Ke ngoko, amanqanaba eNaHS okwenyani kwezi zifundo anokuba phantsi kunalawo axeliweyo.
“Ingaba ikhompawundi ehlala ixesha elifutshane kangaka ingaba nefuthe elihlala ixesha elide njani?” UPozgay et al.21 babuze lo mbuzo xa bevavanya iziphumo zeNaHS kwi-colitis kwiimpuku. Banethemba lokuba izifundo ezizayo ziya kukwazi ukuphendula lo mbuzo kwaye baqikelela ukuba izisombululo zeNaHS zinokuba ne-polysulfides ezizinzileyo ngakumbi ukongeza kwi-H2S kunye ne-disulfides ezilawula isiphumo seNaHS21. Enye into enokwenzeka kukuba amazinga aphantsi kakhulu e-NaHS asele kwisisombululo nawo anokuba nefuthe eliluncedo. Enyanisweni, u-Olson et al. banike ubungqina bokuba amanqanaba e-micromolar e-H2S egazini awangowemvelo kwaye kufuneka abe kuluhlu lwe-nanomolar okanye angabikho kwaphela13. I-H2S inokusebenza nge-protein sulfation, utshintsho oluguqukayo emva kokuguqulwa oluchaphazela umsebenzi, uzinzo, kunye nendawo yeeproteni ezininzi52,53,54. Enyanisweni, phantsi kweemeko zomzimba, malunga ne-10% ukuya kwi-25% yeeproteni ezininzi zesibindi zi-sulfylated53. Zombini ezi zifundo ziyavuma ukutshatyalaliswa ngokukhawuleza kweNaHS19,23 kodwa ngokumangalisayo zithi “silawule ukuxinana kweNaHS emanzini okusela ngokuwatshintsha yonke imihla.”23 Olunye uphando ngempazamo luthi “iNaHS ngumnikeli oqhelekileyo we-H2S kwaye isetyenziswa rhoqo kwizonyango ukuze ithathe indawo ye-H2S ngokwayo.”18
Ingxoxo engentla ibonisa ukuba i-NaHS ilahleka kwisisombululo ngenxa yokuguquguquka, ukuxinana kunye ne-photolysis, ngoko ke kukho iingcebiso ezithile ezenziweyo zokunciphisa ukulahleka kwe-H2S kwisisombululo. Okokuqala, ukuxinana kwe-H2S kuxhomekeke kujongano lwegesi-ulwelo13 kunye ne-pH yesisombululo11; ke ngoko, ukunciphisa ukulahleka kokuxinana, intamo yebhotile yamanzi inokwenziwa ibe ncinci kangangoko njengoko kuchaziwe ngaphambili15,19, kwaye i-pH yamanzi inokulungiswa ukuya kumda ophezulu owamkelekileyo (oko kukuthi, 6.5–8.551) ukunciphisa ukulahleka kokuxinana11. Okwesibini, ukuxinana kwe-H2S okuzenzekelayo kwenzeka ngenxa yeziphumo zeoksijini kunye nokuba khona kwee-ion zesinyithi eziguqukayo emanzini okusela13, ngoko ke ukuxinana kwamanzi okusela nge-argon okanye i-nitrogen44,45 kunye nokusetyenziswa kwe-metal chelators37,47 kunokunciphisa ukuxinana kwe-sulfides. Okwesithathu, ukuthintela ukuxinana kwe-H2S nge-photo, iibhotile zamanzi zinokusongwa nge-aluminium foil; Le ndlela ikwasebenza nakwizinto ezinobuthathaka ekukhanyeni ezifana ne-streptozotocin55. Okokugqibela, iityuwa ze-sulfide ezingaphiliyo (i-NaHS, i-Na2S, kunye ne-CaS) zinokufakwa nge-gavage endaweni yokunyibilikisa emanzini okusela njengoko bekuxeliwe ngaphambili56,57,58; izifundo zibonise ukuba i-sodium sulfide ene-radioactive enikezelwa nge-gavage kwiigundane ifunxwa kakuhle kwaye isasazwa phantse kuzo zonke izicubu59. Ukuza kuthi ga ngoku, uninzi lwezifundo luye lwafaka iityuwa ze-sulfide ezingaphiliyo ngaphakathi kwesisu; nangona kunjalo, le ndlela ayisetyenziswa rhoqo kwiindawo zonyango60. Kwelinye icala, indlela yomlomo yeyona ndlela ixhaphakileyo nekhethwayo yokusetyenziswa ebantwini61. Ke ngoko, sicebisa ukuvavanya imiphumo yabanikeli be-H2S kwiimpuku nge-gavage yomlomo.
Umda kukuba silinganise i-sulfide kwisisombululo samanzi kunye ne-serum sisebenzisa indlela ye-MB. Iindlela zokulinganisa i-sulfide ziquka i-iodine titration, i-spectrophotometry, indlela ye-electrochemical (i-potentiometry, i-amperometry, indlela ye-coulometric kunye nendlela ye-amperometric) kunye ne-chromatography (i-gas chromatography kunye ne-high-performance liquid chromatography), phakathi kwazo eyona ndlela isetyenziswa kakhulu yi-MB spectrophotometric method62. Umda wendlela ye-MB yokulinganisa i-H2S kwiisampulu zebhayoloji kukuba ilinganisa zonke iikhompawundi ezine-sulfur kwaye ayizizo i-H2S63 ekhululekileyo kuba yenziwa phantsi kweemeko ze-asidi, nto leyo ekhokelela ekukhutshweni kwe-sulfur kumthombo webhayoloji64. Nangona kunjalo, ngokutsho kwe-American Public Health Association, i-MB yindlela eqhelekileyo yokulinganisa i-sulfide emanzini65. Ke ngoko, lo mda awuchaphazeli iziphumo zethu eziphambili ekungazinzini kwezisombululo ezine-NaHS. Ngaphezu koko, kuphononongo lwethu, ukubuyiselwa komlinganiselo we-sulfide kwiisampulu zamanzi kunye ne-serum ezine-NaHS yayiyi-91% kunye ne-93%, ngokwahlukeneyo. La maxabiso ahambelana noluhlu oluchazwe ngaphambili (77–92)66, olubonisa ukuchaneka okwamkelekileyo kohlalutyo42. Kubalulekile ukuqaphela ukuba sisebenzise zombini iimpuku ezingamadoda neziziimazi ngokuhambelana nezikhokelo zeNational Institutes of Health (NIH) ukuze siphephe ukuthembela kakhulu kwizifundo zezilwanyana ezingamadoda kuphela kwizifundo zangaphambi kweklinikhi67 kwaye sibandakanye zombini iimpuku ezingamadoda neziziimazi nanini na xa kunokwenzeka68. Eli nqaku ligxininiswe ngabanye69,70,71.
Ukuqukumbela, iziphumo zolu phononongo zibonisa ukuba izisombululo ze-NaHS ezilungiselelwe ngamanzi okusela azinakusetyenziselwa ukuvelisa i-H2S ngenxa yokungazinzi kwazo. Le ndlela yokusetyenziswa ingabeka izilwanyana kumanqanaba angazinziyo naphantsi kunokulindelekileyo e-NaHS; ngoko ke, iziphumo zisenokungasebenzi ebantwini.
Iiseti zedatha ezisetyenzisiweyo kunye/okanye ezihlalutyiweyo ngexesha lophando lwangoku ziyafumaneka kumbhali ohambelanayo xa kuceliwe ngokufanelekileyo.
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