| Purpose:A new view points that DR is not only a retinal microvascular damage but also a chronic degeneration of nerve tissue. The changes of neurons and glial might be the major factors for retinal vascular disease. The change of ganglion cells and Muller cells caused by diabetes should occur as early as there is evidence of vascular lesions. My research was designed to assess the expression of GFAP,GLAST,GS,NT-3 in glial cells(Muller cells) and the damage of RGCs in rats by DM and discuss the effection to retinal neurons by DM, observe the neurologically protective role of Chinese medicine, analyzes its nerve protective mechanism and find a way to prevent and cure DR by Chinese medicine..Methods:82 male SD rats (weight between 180g and 220g) are randomly divided into 4 groups:model group,control group, treatment group and normal group. The rats were injected STZ (65 mg/kg weight) peritoneanouly and those with a blood glucose level higher than or equal to 16.7 mmol/L are DM model rats. Rats in treatment group and normal group were with QiShenYiQI pills and DuoBeiShi pills (1.5g/kg weight) each day. Blood glucose level and body weights were measured regularly. Experiment lasts for 300 days. Carotid bloodletting executed rats.The eyeballs were removed and retinal slides were made. Retinal structure was observed by optical microscope and electron microscopy. The expression level of GFAP mRNA was detected by the method of RT-PCR. Apoptosis of RGCs and cells in retinal kernel layer were measured by Tunel and the apoptotic cells were counted. LSAB method was used to measure the expression level of GFAP,GLAST,GS,NT-3. Immunological histochemistry assay was used for quantitative analysis. SPSS was used for statistical analysis..Results:(1) Weight of diabetic rats were significantly lower than normal group (P<0.01) and there is no significant differences in weight of treatment group, control group and the model of rats (P>0.05). (2) Glucose in diabetic rats were markedly higher than normal group (P<0.01) and there is no significant differences in glucose in treatment group, control group and the model of rats(P> 0.05). (3) Compared to normal group, the expression of GFAP mRNA by RT-PCR in diabetic rats was enhanced significantly. Compared to model group, the expression in treatment group and control group was decreased. Compared to control group, the expression in treatment group was decreased. (4) The positive apoptotic retinal cell were only expressed in RGCs and inner nuclear layer. The number of apoptotic RGCs and cells in inner nuclear layer in model group,control group and treatment group was significantly higher than in normal group. Compared to model group, the number of apoptotic cells in control group and treatment group decreased obviously. Compared to control group, the number of apoptotic cells in treatment group decreased obviously. (5) Compared to normal group, the positive expression of GFAP in diabetic rats by LSAB was enhanced significantly. Compared to model group,the expression in treatment group and control group was decreased. Compared to control group, the expression in treatment group was decreased (6) Compared to normal group, the positive expression of GLAST by LSAB in model group,control group and treatment group was decreased significantly. Compared to model group and control group, the expression in treatment group was enhanced. (7) Compared to normal group, the positive expression of GS by LSAB in model group,control group and treatment group was decreased significantly. Compared to model group, the expression in treatment group and control group was enhanced. Compared to control group, the expression in treatment group was increased. (8) Compared to normal group, the positive expression of NT-3 by LSAB in control group, model group and treatment group was decreased significantly. Compared to model group, the expression in treatment group and control group was enhanced. Compared to control group, the expression in treatment group was increased. (9) The number of apoptotic RGCs and cells in inner nuclear layer was correlated positively with the positive expression level of GFAP, while the expression of GLAST,GS and NT-3 was negatively.Conclusion:1 The apoptotic cells number in RGCs and the inner nuclear layer in diabetic rats retina were significantly increased.2 The expression of GFAP in Retinal Muller cells in diabetic rats increases and Muller cells are in active proliferation of glial reactive state.3 The function of GLAST and GS iin diabetic retinal Muller cells is weakened and its ability of transporter glutamate is declined.4 Qishenyiqi pills has a protective effect to retinal nerve cells in diabetic rats. Its mechanism is as follows.(1)Qishenyiqi pills can inhibit the overexpression of GFAP and glial cell reactive hyperplasia in Muller cells and reduce the damage to the Muller cell function and retinal neurons by DM.(2)Qishenyiqi pills can promote the expression of GLAST and GS in Muller cells and remove the excessive extracellular glutamate effectively and reduce the high concentrations of the role of glutamate excitotoxicity. (3) Qishenyiqi pills can promote the expression of neurotrophic factors (NT-3) and reduce the the number of apoptotic neural cells.
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