Isihloko
I-methylene blue ocwaningweni lwesifo sohlangothi nokugeleza kwegazi okuncishisiwe ebuchosheni: lokho amamodeli amathathu akubonisayo ngempela
Umthambo ovalekile, amaseli akhuliswe elabhorethri ancishwe izakhi eziwondlayo, negundane elinemithambo yentamo emincane kungase kuzwakale kuyizinhlobo ezintathu zokuhlola okukodwa. Akunjalo. Ngakunye kubuza umbuzo ohlukile, futhi i-methylene blue inikeza impendulo ehlukile kukho ngakunye. Uma ukudidanisa, imibhalo yocwaningo ibukeka iphikisana. Uma ukuhlukanisa, kuvela iphethini ecacile, elawulwa kakhulu isikhathi sokunikeza umuthi.
Lokho kuhlukanisa kuyiyona nhloso yalokhu kubuyekezwa. Amamodeli amathathu yisifo sohlangothi esiqala ngokuzumayo endaweni ethile, ukuntuleka komoya-mpilo neglucose okulandelwa ukubuyiselwa komoya-mpilo kumaseli akhuliswe elabhorethri, nokugeleza kwegazi okuncishisiwe ebuchosheni okuhlala amasonto. Indlela yokusebenza ehlongozwayo ewaxhumanisayo ithinta ama-mitochondria, kodwa imiphumela iyahlukahluka ngoba izimo zemetabolism ziyahlukahluka.
Amamodeli amathathu aphendula imibuzo ehlukene
Isifo sohlangothi esiqala ngokuzumayo endaweni ethile ebuchosheni bamagundane ngokuvamile sidalwa ngokuvala umthambo wobuchopho ophakathi nendawo, okufushaniswa ngokuthi MCAO. Ukuvaleka okufana nehlule legazi kwakha umongo ontula igazi ozungezwe i-penumbra, izicubu ezisengozini kodwa ezingase zisindiswe uma ukugeleza kwegazi kubuya. Umbuzo lapha ukuthi ukungenelela kuyakunciphisa yini ukukhula kwendawo yezicubu ezifile noma kugcine ukusebenza kwezicubu ngesikhathi sokubuyiselwa kokugeleza kwegazi.
Ukuntuleka komoya-mpilo neglucose, okufushaniswa ngokuthi OGD, kusebenza ezingeni elincane kakhulu. Amaseli obuchopho akhuliswe elabhorethri afakwa esimweni esinomoya-mpilo ocishe ungabikho, ngaphandle kweglucose, bese ebuyiselwa endaweni evamile yokuwakhulisa. Alikho ihlule legazi, akukho ukujikeleza kwegazi ngeminye imithambo, akukho mfutho wegazi, futhi akukho masosha omzimba. Umbuzo uthinta amaseli kuphela: kwenzekani ekuphefumuleni kwamaseli, ku-ATP, nasekusindeni kwawo lapho izinto azisebenzisayo ukukhiqiza amandla zinyamalala bese zibuya.
Ukucwaninga ukugeleza kwegazi okuncishisiwe ebuchosheni okuhlala isikhathi eside kusebenzisa ukuvalwa unomphela kwemithambo ye-carotid ezinhlangothini zombili zamagundane, okubizwa ngemodeli ye-2VO. Ukugeleza kwegazi engxenyeni engaphambili yobuchopho kuyehla futhi kuhlale kuphansi amasonto. Akukho ukufa kwezicubu endaweni ethile okuqala ngokuzumayo futhi akukho ukubuyiselwa kokugeleza kwegazi okuphuthumayo. Umbuzo ukuthi ukusekelwa kwemetabolism amasonto amaningi kuyayilondoloza yini imithambo, ama-mitochondria, nenkumbulo ngesikhathi sokugeleza kwegazi okuphansi isikhathi eside.
Ngakho-ke ukuthuthuka kwenkumbulo ngemva kwenyanga eyodwa yokwelashwa kumodeli ye-2VO akusho lutho oluqondile ngokusindisa ubuchopho bomuntu ngesikhathi sokuhlinzwa okuphuthumayo kokukhipha ihlule legazi. Lo mehluko ubalulekile ngoba izifinyezo eziningi ezinethemba ziyawushiya.
Isifo sohlangothi esiqala ngokuzumayo: ukuvikelwa lapho ukugeleza kwegazi kubuyiselwa, ukubambezeleka uma kungabuyiselwa
Umphumela ocacile kakhulu wesimo esiqala ngokuzumayo uvela ku-MCAO yesikhashana elandelwa ukubuyiselwa kokugeleza kwegazi. Imithambo yamagundane yavalwa imizuzu engu-60, kwase kunikezwa i-methylene blue ngomthamo ophansi emthanjeni kusukela ngesikhathi sokubuyiselwa kokugeleza kwegazi, kwalandelwa eminye imithamo ngemva kwamahora angu-3 nangosuku lwesi-2. I-MRI yabonisa ukuthi indawo eyonakele eqenjini elathola uketshezi oluthwala umuthi ngaphandle komuthi yakhula cishe ngamaphesenti angu-19 ngosuku lwesi-2, kuyilapho indawo eyonakele eqenjini elalashwa yancipha cishe ngamaphesenti angu-17. Izindawo zokugcina zezicubu ezifile zazincane cishe ngamaphesenti angu-30, futhi amaphuzu okuhlolwa kokusebenza kwezinzwa ayengcono ngezinsuku zesi-2 nesi-7. Ukusinda kwezicubu zomongo nezase-penumbra njengoba kubonakala ezithombeni kwathuthuka. Imibhalo ebanzi ngokuvikelwa kwezinzwa ibeka lokhu kuvikelwa okuhambisana nesikhathi sokubuyiselwa kokugeleza kwegazi eceleni kwemiphumela yokuntuleka kwegazi ebuchosheni bonke nokulimala.
Isimo siyashintsha lapho umthambo uhlala uvalekile. Ekuhlolweni kwe-MCAO yaphakade, i-methylene blue eyanikezwa ngesikhathi ukuntuleka kwegazi kusaqhubeka yanciphisa ijubane lokwanda kwendawo eyonakele ebonakala ezithombeni zokusabalala kwamanzi futhi yelula okwesikhashana ukungahambisani phakathi kwezindawo zokugeleza kwegazi nokusabalala kwamanzi, nokugeleza kwegazi kwendawo okungcono kancane. Kodwa umthamo wokugcina wezicubu ezifile ngemva kwamahora angu-24 wawungehlukile ngendlela ebalulekile ngokwezibalo. Yabambezela ukuguquka kwezicubu ezisengozini zibe ezifile, kodwa ayizange ithathe indawo yokuvulwa kabusha komthambo.
Ucwaningo lwesithathu lwesimo esiqala ngokuzumayo lwengeza imininingwane yendlela yokusebenza nomehluko wemithamo. Umthamo owodwa owafakwa emgodini wesisu ngokushesha ngemva kokuvalwa komthambo wabonisa ukuncipha okukhulu kunakho konke kwendawo yezicubu ezifile, cishe ngamaphesenti angu-50, ngomthamo ophakathi nendawo ongu-5 mg/kg kuno-1 noma u-10 mg/kg, kanye namaphuzu angcono okuhlolwa kwemizwa nokunyakaza. Ababhali baxhumanisa lokhu nokulondolozwa kwesakhiwo sama-mitochondria nokwanda kwe-mitophagy, okuwukususwa ngokukhetha kwama-mitochondria alimele. Ngakho umthamo, indlela yokunikeza umuthi, neshejuli kubalulekile, futhi amanani e-mg/kg asetshenziswa emagundaneni akuwona imithamo yabantu abanesifo sohlangothi.
Amaseli akhuliswe elabhorethri: umuthi ofanayo uyasiza noma ulimaze kuye ngokuthi ufika nini
Ukuhlolwa kwama-astrocyte kufundisa kakhulu futhi yikho okucashunwa kabi kakhulu. Ama-astrocyte athathwe ngokuqondile ku-cortex yamagundane amancane afakwa amahora angu-6 esimweni sokuntuleka okukhulu kwezinto eziwondlayo, emoyeni-mpilo ongamaphesenti angu-0.1, endaweni yokuwakhulisa engenayo iglucose, i-pyruvate, noma i-serum. Lokhu kwalandelwa amahora angu-24 okubuyiselwa komoya-mpilo kanye nezinto ezisetshenziselwa ukukhiqiza amandla. Cishe uhhafu wamaseli wafa, okwenza lokhu kuhlola kube nethuba lokubonisa imiphumela kunoma yiluphi uhlangothi.
Lapho i-methylene blue ikhona ngesikhathi sokuntuleka, ukusinda kwaba kubi kakhulu, akuzange kube ngcono. Lapho kunalokho ifakwa ngesikhathi sokubuyiselwa komoya-mpilo, amazinga aphansi e-micromolar athuthukisa ukuphila kwamaseli futhi akhulisa ukusetshenziswa komoya-mpilo, ukufakwa kweglucose kumaseli, nokukhiqizwa kwe-ATP. Ezimweni ezivamile, amazinga afanayo akhulisa ukufakwa kweglucose kumaseli cishe ngamaphesenti angu-89 ku-0.1 micromolar nangamaphesenti angu-200 ku-1 micromolar, kwagcinwa iglycogen nokusebenza kwe-hexokinase ngemva kokulimala, futhi akuzange kukalwe ukwanda kwe-superoxide.
Indlela yokusebenza iqondakala kalula uma iqhathaniswa nejeneretha eyisipele. I-methylene blue isebenza njengesithwali sama-electron esingasetshenziswa njengenye indlela, esamukela izinto ezinikela ngama-electron bese siwadlulisela ku-cytochrome c naku-complex IV. Lokhu kusekela ukugeleza kwama-electron nokwakhiwa kwe-ATP kuyilapho kunciphisa ukuvuza kwama-electron ezigabeni ezingaphambili. Ngesikhathi sokuntuleka okukhulu, lokho kukhuthazwa kuyingozi ngoba kwandisa isidingo semetabolism lapho umoya-mpilo neglucose kucishe kungabikho, okungaqeda izinqolobane zokugcina ngokushesha. Ngemva kokubuya kwezinto ezisetshenziselwa ukukhiqiza amandla, leso sici siyazuzisa ngoba sisiza ama-mitochondria alimele ukuba asebenzise kahle umoya-mpilo neglucose okubuyiselwe. Yingakho nemiphumela evela ezincazelweni zokudluliswa kwama-electron kuma-mitochondria idinga ukuhambisana nomongo wesimo sokuntuleka.
Isixwayiso esisodwa: lo mthetho wesikhathi usebenza kulawo ma-astrocyte alungiselelwe ukuhlolwa. Olunye ucwaningo oluhambisana nalo, olusebenzisa uhlobo oluhlukile lwamaseli, ukuntuleka okuncane, nezinga lomuthi eliphansi, lwathola ukuvikelwa ngisho nalapho umuthi ufakwa ngesikhathi sokuntuleka. Uhlobo lwamaseli, umoya-mpilo osele, izinga lomuthi, nenqubo yokuhlola kunquma ukuthi umphumela uyasiza noma uyalimaza.
Ukugeleza kwegazi okuphansi okuhlala isikhathi eside: inkumbulo, i-cytochrome oxidase, nemithambo phakathi namasonto
Ukuhlola kwezimo ezihlala isikhathi eside kwasebenzisa ukwelashwa kwansuku zonke ngomthamo ophansi amasonto amaningi, hhayi umthamo owodwa onikezwa ngokushesha esimweni esiphuthumayo. Ocwaningweni lokuqala, amagundane anemithambo ye-carotid evalwe unomphela athola u-4 mg/kg nsuku zonke inyanga eyodwa, ngemva kweseshini ngayinye yokuqeqeshwa kwansuku zonke, ukuze kuqondiswe ekuqinisweni kwenkumbulo kunokusebenza ngokushesha. Izilwane ezinemithambo evalekile zafunda kancane imisebenzi yokuhlukanisa izinto ngokuzibona futhi zenza kabi kakhulu ekuhlolweni okunzima kwenkumbulo, kuyilapho ikhono lokubhukuda, ukunyakaza, nokubona iphunga kungathintekanga. Ukwelashwa kwansuku zonke kwanciphisa ukuphazamiseka kokufunda nenkumbulo ngaphandle kokushintsha ukuziphatha okuvamile kokunyakaza.
Ucwaningo olulandelayo lwahlola ukusabalala kwe-cytochrome oxidase, okuyi-complex IV yama-mitochondria, ezindaweni zobuchopho ezingu-44 ngemva kweshejuli efanayo yenyanga eyodwa. Ukuvaleka kwehlisa ukusebenza kwe-enzyme ku-cortex yokubona, ku-cortex engaphambili, naku-cortex ye-perirhinal, kanye naku-hippocampus ne-amygdala, futhi kwenza buthaka ukusebenza okuhambisanayo phakathi kwe-cortex yokubona ne-hippocampus. Ukwelashwa kwalondoloza ukusebenza kwe-enzyme ezindaweni ezithile futhi kwaqinisa lokho kuhlobana kwemetabolism phakathi kwezindawo, kanti ukusebenza okwalondolozwa kwakuhlotshaniswa nokwenziwa kwemisebenzi okungcono. Lokhu kuhlobana kuchaza ukusebenza okuhambisanayo kwama-enzyme emetabolism, hhayi izilinganiso eziqondile zokuxhumana kokusebenza kobuchopho bomuntu, iphuzu ukubuyekezwa kwemetabolism yamandla obuchopho okusiza ukuba licace.
Olunye ucwaningo oluhlukile lwesonto elilodwa lwasebenzisa u-2 mg/kg nsuku zonke futhi lwengeza isivimbeli sendlela yokusebenza ukuze luhlole indlela umuthi osebenza ngayo. Ukugeleza kwegazi ebuchosheni kwakhuphuka kusuka cishe ku-60 kuya cishe ku-100 mL nge-100 g ngomzuzu ngokwelashwa, futhi ukuminyana kwemithambo ku-hippocampus kwakhuphuka kusuka cishe kumaphesenti angu-15.1 kuya ku-23. Kokubili lokhu kuthuthuka kwahlehla ngokwengxenye lapho indlela yokusinda kwamaseli ye-PI3K/Akt ivinjelwa, futhi i-Akt efakwe i-phosphate yanda ngokwelashwa. Imiphumela yokugeleza kwegazi, ukuminyana kwemithambo, isithiyo, namaseli ezinzwa ikhomba ukuvikelwa kwezinzwa nemithambo okuhlobene nokudluliswa kwezimpawu nge-PI3K/Akt kunomphumela wemetabolism kuphela.
Kungani konke lokhu kungalingani nokunakekelwa okuphuthumayo kwesifo sohlangothi
Ukulawulwa kwezimo elabhorethri kuyisizathu sokuthi le miphumela ingadluliseki ngokuqondile. Amaseli akhuliswe elabhorethri awanalo ihlule legazi noma izinqubo zomzimba zokumunca, ukusabalalisa, ukuguqula nokukhipha umuthi. Imodeli ye-2VO iwukugeleza kwegazi okuphansi ebuchosheni bonke okuhlala isikhathi eside, hhayi ihlule elifika ngokuzumayo livale umthambo endaweni ethile ne-penumbra esinemizuzu embalwa ikhona. Ngisho ne-MCAO yamagundane isebenzisa izilwane ezisencane neziphilile, izinzwa zokulalisa, ukuvaleka okufanayo, nokunikezwa kwemithamo ngezikhathi ezinembile, ngokungafani neziguli ezindala ezinamahlule ahlukahlukene, ukuqina nokuncipha kwemithambo ngenxa yama-plaque, umfutho wegazi ophakeme, isifo sikashukela, nezikhathi zokuqala kwesifo ezingaziwa.
Akukho ukuhlolwa kwabantu okushicilelwe, okwabela ababambiqhaza emaqenjini ngokungahleliwe, okuqinisekise i-methylene blue njengokwelashwa okuphuthumayo kwesifo sohlangothi esiqala ngokuzumayo ngenxa yokuntuleka kwegazi. Ucwaningo lwezithombe zobuchopho babantu olucashunwa ngezinye izikhathi lwabandakanya abantu abadala abangu-26 abaphilile, hhayi iziguli zesifo sohlangothi, futhi umthamo owodwa ophuzwa ngomlomo washintsha izimpawu zobuchopho ezihlobene nomsebenzi, ngokuthuthuka okuncane ekukhumbuleni ulwazi. Lokho kubonisa ukusebenza emithanjeni yezinzwa ephakathi, hhayi ukusebenza ngempumelelo ekwelapheni isifo sohlangothi. Iziqondiso zamanje zezimo eziphuthumayo kunalokho zigxile ekubuyiseleni ukugeleza kwegazi ngokushesha ngemithi encibilikisa amahlule efakwa emthanjeni ezigulini ezifanelekile, nasekukhipheni amahlule uma ukuvaleka kwemithambo emikhulu kufanelekile. Izinqubo ezijwayelekile zokunakekelwa okuphuthumayo kwesifo sohlangothi ziseyindlela kuphela eqinisekisiwe. Ukunakekelwa kwesifo sohlangothi esisolwayo akufanele kubambezeleke ukuze kunikezwe i-methylene blue, futhi imikhawulo yokusebenzisa kubantu imithamo ethathwe ocwaningweni lwangaphambi kokuhlolwa kubantu ichaza ukuthi kungani amashejuli amagundane engafundwa njengamashejuli okwelapha iziguli.
Izindaba zokuphepha ziqinisa lowo mngcele. I-methylene blue efakwa emthanjeni inesixwayiso esisebhokisini ngesifo se-serotonin esibi noma esibulalayo lapho ihlanganiswa nemithi ethinta i-serotonin, kuhlanganise nama-SSRI, ama-SNRI, nezivimbeli ze-MAO, ethathwa iziguli eziningi eziseminyakeni lapho isifo sohlangothi sivame khona. Akufanele isetshenziswe kubantu abantula i-G6PD ngenxa yengozi yokubhidlika kwamangqamuzana abomvu egazi. Iphinde ivimbele ukudluliswa kwezimpawu nge-nitric oxide, okwandisa ukumelana kwemithambo nokugeleza kwegazi kanye nomfutho kwezinye izimo, ngakho akufanele ichazwe nje njengomuthi owandisa ukugeleza kwegazi ebuchosheni. Ishejuli egunyaziwe ka-1 mg/kg efakwa emthanjeni yokwelapha i-methemoglobinemia etholakele ayiyona ishejuli yesifo sohlangothi.
Isifinyezo esithembekile sinomkhawulo kodwa sisekelwe emiphumeleni yangempela. Ngesikhathi esiseduze nokubuyiselwa kokugeleza kwegazi ekuntulekeni kwegazi kwesikhashana endaweni ethile, i-methylene blue ngomthamo ophansi yanciphisa ukuqhubeka kokulimala emagundaneni. Lapho ukuvaleka kungokwaphakade, yabambezela kodwa ayivimbelanga ukufa kwezicubu. Kuma-astrocyte, yalimaza ngesikhathi sokuntuleka okukhulu futhi yasiza lapho umoya-mpilo ubuyiselwa. Ngesikhathi sokugeleza kwegazi okuncishisiwe okuhlala isikhathi eside, yalondoloza i-cytochrome oxidase, imithambo, nenkumbulo phakathi namasonto. Isithwali esisodwa, izimo ezintathu, izimpendulo ezintathu.