Effects Of Melatonine On Diabetic Retinal Müller Cell

ObjectiveIn the present study,we aimed to explore the anti-oxidative stress effect of melatonin(MLT)on diabetic retinal Müller cell,and to clear the mechanisms of diabetic retinopathy(DR)as well as give an inspiration to the treatment of DR.MethodsSD rats 200~230 g were administered with streptozotocin at dose of 60mg/kg for a single intraperitoneal injection to induce diabetic model.Only Rats with glycemia more than 16.7 mmol/L 24 hour after injection were used as diabetic models.The experiment was conducted in 3 groups named MLT-treated group,diabetic group and control group.Rats were detected 3month after diabetic onset.We observed the content of retinal malondialdehyde(MDA)and(reduced glutathione,GSH),the expression of glial fibrillary acidic protein(GFAP)and glutamine synthetase(GS)in retina,and the alteration of morphological location of GFAP in retina,and the level of retinal glutamate with high efficiency liquid chromatography(HPLC),the density of retinal ganglion cell(RGC)with HE staining.ResultsIn control group,diabetic group and MLT-treated group,the level for GSH were(95.3±7.5),(73.1±6.1),(92.6±8.5)mg/g prot,for MDA were(0.23±0.05),(0.42±0.10),(0.27±0.08)μmol/g,for immumohistochemical GFAP were(100.0±0.0),(356.6±22.8),(110.3±9.6)%.Western blot showed that the expression of GFAP were(19.2±3.8),(51.6±6.8),(22.2±6.3)%,of GS were(55.7±5.1),(32.6±3.8),(54.1±5.5)%in control group,diabetic group and MLT-treated group respectively.HPLC showed that the level of retinal glutamate were(34.8±5.7),(44.3±5.2),(35.6±6.1)μmol/g in control group,diabetic group and MLT-treated group.Compared with control group,increased MDA,glutamate and GFAP were observed as well as decreased GSH and GS in diabetic group(P<0.01).No alterations of retinal MDA,GSH,GFAP,glutamate and GS were revealed between control group and MLT-treated group(P>0.05).The density of RGC in control group,diabetic group and MLT-treated group were(1319±351),(886±198),(1126±348)/mm~2 respectively,Compared with control group,the density of RGC was decreased in diabetic group,showing no alteration in MLT-treated group(P>0.05).ConclusionsMLT inhibits oxidative stress in DR,reversing the expression of GS in Müller cell and inhibiting the accumulation of glutamate in diabetic retina,and therefore,protects RGC.