Study On The Protection Of Lyceum Barbarum Polysaccharides To Retina Of Diabetic Rats

Objective: To observe the changes and influences of Lycium barbarumpolysaccharides on streptozotocin (streptozotocin, STZ) in diabetic rat retinapathological, as well as on retinal vascular endothelial growth factor (vascularendothelial growth factor, VEGF) and blocking protein (Occludin) expression,to explore the protective effect of Lycium barbarum polysaccharides on theretina of diabetic rats and its mechanism.Method: Fifty-five adult SD rats were randomly divided into normal group(CON group) of fifteen and diabetes group (DM group) of forty. DM group ratswere injected STZ to establish the diabetic model, except one failed. The rest ofthirty nine model rats were randomly divided into the LBP treatment group(LBP group) of eighteen and DM saline group (Nacl group) diabetes group oftwenty-one. LBP rats were given Lycium barbarum polysaccharides the dailytiming quantitative gavages (160mg/kg/d), until the day before being killed.And an equal volume of normal sodium was administrated to the Nacl group.The three groups of rats were reared for4weeks,12weeks, and20weeks andgiven blood glucose measured, then killed. To observe the general state of ratsin each group, record blood glucose value of them at different period.Observation rat diabetes retina pathological change was measured in rat retinasusing HE staining and observation rats diabetes retina pathological expressionof VEGF and Occludin was measured in rat retinas using immunohistochemistry.Result:1. The diabetic rat model was successfully established. According to the measurement of blood glucose of rats in each group can get the results:Blood glucose concentration of CON group rats is always lower than6.00mmol/L; With gavages to diabetic rats for4weeks,12weeks,20weeks, bloodglucose concentration of Nacl group continued to increase, at4weeks was27.1±4.23mmol/L, at12weeks increased to2.82±5.41mmol/L, at20weeksreached to2.91±6.27mmol/L; But blood glucose concentration of LBP groupwere significantly lower than the Nacl group at the same time point (p <0.01), at4weeks was11.8±4.13mmol/L, at12weeks was14.6±3.89mmol/L; at20weeks was15.8±3.99mmol/L.2. The retina of diabetic rats histological HE staining showed that indiabetic rats after administration of the first four weeks, twelve weeks, twentyweeks, CON rats retinal had no significant anomalies. At4weeks, Nacl grouphad the pathological retinal damage; the LBP group rat retina had no significantanomalies. At12weeks, the Nacl group and LBP rats had the pathologicalretinal damage, Nacl groups of rats with lesions were worse than the LBP group,and the lesions became worse and worse. At20week, Cells in each layer ofretina arranged in haphazard, the number reduced significantly, and theexpansion of capillary was obvious. Compared with the Nacl group at the sametime, LBP group was better. The retina was thicker, layers of cells arranged inorder; a large number of cells were more, capillary dilatation was not so much.The retinal pathological damage was slighter than that in Nacl group.3. Retinal immunohistochemical staining:1) VEGF expression in theretina: the amount of VEGF expression in diabetic rats after administration ofthe three time points of the first four weeks, twelve weeks, twenty weeks, VEGFof CON rats had no significant change. Nacl group at4weeks, the expressionlevel of VEGF had significant differences (p <0.05) compared with the CON group, and with the development of the disease, rat retinal VEGF expressionincreased. At the12weeks,20weeks, and the expression level were statisticallysignificant (p <0.01) compared with the CON group. LBP rats retinal VEGFexpression levels in4weeks was no significant difference (p>0.05), atcompared with the CON group, the amount of VEGF expression increased at the12th weeks. With statistical significance as compared with CON group (p<0.05),and the VEGF expression also increased with the progression, but significantlylower than those of the Nacl group (p<0.01).2) Occludin expression in the retina: in diabetic rats after administration ofthe first four weeks, twelve weeks, twenty weeks, the positive expression ofOccludin in the rat retina was brown; the expression had no obvious change.NaCl group at4weeks, the expression level of the CON group showed nosignificant difference (p>0.05), with the duration of the development of ratretinal Occludin expression of steady decline,12weeks,20weeks, and theexpression level CON group were statistically significant (p <0.01). But therewere no significant difference between the Occludin expression of LBP groupand CON group at the4weeks,12weeks (p>0.05),20weeks, Occludinexpression decreased, there was statistically significant compared with groupCON (p<0.05), but its expression is still higher than the Nacl group, there wasstatistical significance (p<0.05)Conclusion: LBP can significantly reduce the blood glucose concentrationin diabetic rats; improve the pathological injury of retina effectively. Inhibitingthe increases ion of retinal VEGF expression to prevent the formation of retinalneovascularization. Raising Occludin expression levels, stable micro vascularretinal vascular endothelial tight junctions, which has a protective effect of LBPon the destruction of the of diabetes blood-retinal barrier.