Protective Effect Of Crocetin On Retinal Neuroepithelial In Streptozotocin Induced Diabetic Rat

Objective:To detect the protective effect of crocetin on retinal neuroepithelial in streptozotocin induced diabetic rat and uncover the underlying mechanism.Methods :Choose forty male Sprague-Dawley(SD)rats,randomly divided into normal control(CON)group(ten rats),diabetic model(DM)group(thirty rats).Selecting randomly thirty rats intraperitoneal inject streptozotocin(60mg/kg)induce producing of diabetic rat,when the animal model is success we randomly divided the rat into three groups : diabetic model(DM)group,crocetin low dose(DM+CRO(L))group(50mg/kg/d,p.o.),crocetin high dose(DM+CRO(H))group(100mg/kg/d,p.o.),Crocetin use 0.5% Carboxymethyl Cellulose(CMC)distilled water dissolve,Control(CON)group rats had intraperitoneal injection of same volume saline.DM+CRO(L)and DM+CRO(H)group were gave the corresponding dose crocetin per day,CON group and DM group were gave 3ml 0.5% CMC distilled water per day.In the end of eighth week,we record the serum glucose level of each group and then all rats were sacrificed and took all eye balls to be detected the expression level of caspase3 by Immunohistochemical,and the retinal thickness and retinal histomorphology changes,and detecting the protein expression levels of Protein kinase C(PKC),and detecting the mRNA expression levels of Bcl-2,TNF-a,PKC-βby quantitative realtime fluorescence polymerase chain reaction(qRT-PCR).Results:1.The rats blood glucose level of DM+CRO(H)and DM+CRO(L)group versus DM group was decreased.2.In the DM group,the thickness of the retinal neuroepithelial was thinner than that of the CON group,and the outer nuclear layer,inner nuclear layer and ganglion cell layer were more disordered.The DM+CRO(H)and DM+CRO(L)group were significantly improved compared with the DM group.3.Immunohistochemistry showed that the DM group compared with CON group of rat retinal ganglion cells and the inner nuclear layer of Caspase3 expression was significantly increased,the expression level of Caspase3 in DM+CRO(H)decreased significantly compared with DM group,DM+CRO(L)group significantly decreased than DM group.4.Western blot results showed that the expression level of PKC in rat retinal neuroepithelial were decreased in DM+CRO(H)group and DM+CRO(L)versus DM group,DM group versus CON group the expression level of PKC were significantly increased.5.QRT-PCR detection showed that TNF-a,PKC beta and Bax mRNA expression in DM+CRO group was significantly lower than DM group,DM group was higher than the CON group,the Bcl-2 expression of mRNA DM+CRO was significantly higher than DM group.Conclusion:Crocetin has protective effect on retinal neuroepithelial in streptozotocin induced diabetic rat,The mechanism may through inhibiting the expression level of apoptosis gene such as TNF-a and Bax,increasing the expression level of anti-apoptosis gene such as Bcl-2,and crocetin Reduce the expression of PKC in retinal neuroepithelial cells and then Inhibit of retinal neovascularization in rats with diabetic retinopathy,and the main mechanism is related to the decrease of PKC beta gene expression.