褪黑素通过调控SLC31A1/FDX1轴对视网膜缺血-再灌注损伤大鼠视网膜铜死亡的作用OA

Objective To investigate the mechanism by which melatonin(Mel)alleviates cuproptosis in rat retinal ischemia-reperfusion injury(RIRI)by regulating the solute carrier family 31 member 1(SLC31A1)/ferredoxin 1(FDX1)axis.Methods Fifty-six healthy,pathogen-free male Sprague-Dawley rats were randomly assigned to the sham surgery(Sham)group(n=15),the RIRI group(n=15),the RIRI+Mel group(n=15),and the Sham+Mel group(n=11),with the right eye as the experimental eye.An acute rat RIRI model was established in the RIRI group and the RIRI+Mel group using the high intraocular pressure(anterior chamber)method.Rats in the Sham group underwent only an anterior chamber puncture after anesthesia.Rats in the RIRI+Mel group and the Sham+Mel group received an intraperitoneal injection of 10 mg·kg-1 Mel 30 minutes before and after modeling.Rats in the Sham group and the RIRI group received an intraperito-neal injection of an equal volume of normal saline.Twenty-four hours after modeling,hematoxylin-eosin(HE)staining was used to observe changes in retinal morphology in the each groups of rats;immunofluorescence and immunohistochemical staining were employed to examine changes in the expression of SLC31A1-positive cells,FDX1-positive cells,lipoic acid syn-thase(LIAS)-positive cells,dihydrolipoamide S-acetyltransferase(DLAT)-positive cells,and heat shock protein 70(HSP70)-positive cells in the retinal of rats;copper ion levels in retinal tissue from rats were measured using spectropho-tometry;the expression levels of SLC31A1,FDX1,LIAS,DLAT and HSP70 in retinal tissue from rats were assessed by West-ern blot.Results Twenty-four hours after modeling,HE staining revealed that,compared with the Sham group,the RIRI group showed significant edema in the retinal tissue of rats,with loosely arranged and disordered retinal ganglion cells(RGCs)and a reduced number of RGCs;compared with the RIRI group,the RIRI+Mel group exhibited a relatively well-ar-ranged retinal structure and an increased number of RGCs(all P＜0.05).Immunofluorescence and immunohistochemistry staining revealed that,compared with the Sham group,the RIRI group exhibited a significant increase in the number of SLC31A1+cells,a decrease in the number of FDX1+cells,and a significant reduction in the number of LIAS+and DLAT+cells,alongside a marked increase in the number of HSP70+cells(all P＜0.05);compared with the RIRI group,the number of SLC31A1+and HSP70+cells in the retinal tissue of rats in the RIRI+Mel group decreased,whilst the number of FDX1+,LIAS+,and DLAT+cells increased;however,these counts had not yet returned to normal levels(all P＜0.05).Copper ion concentration in the retinal tissue of rats in the RIRI group was significantly higher than that in the Sham group;compared with the RIRI group,copper ion concentration in the retinal tissue of rats in the RIRI+Mel group was significantly lower(both P＜0.05).Western blot results showed that,compared with the Sham group,the RIRI group exhibited reduced ex-pression of FDX1,LIAS,and DLAT proteins in the retinal tissue of rats,whilst the expression of SLC31A1 and HSP70 pro-teins were elevated(all P＜0.05);compared with the RIRI group,the RIRI+Mel group exhibited increased expression of FDX1,LIAS,and DLAT proteins and decreased expression of SLC31A1 and HSP70 proteins in the retinal tissue of rats(all P＜0.05).Conclusion Intraperitoneal injection of Mel in rats may alleviate RIRI-mediated cuproptosis in retinal cells by regulating the SLC31A1/FDX1 axis.