Influence Of Bevacizumab Combined With Metformin On Protective Effects And Expression Of VEGF And PAMPK In Diabetic Retinopathy Rats

Objective To study the Influence of Bevacizumab combined with metformin on protective effects and expression of VEGF and p AMPK in diabetic retinopathy rats, and further explore the mechanism.Methods The rat model of diabetes mellitus(DM) was established by high fat feeding and intraperitoneal injection of streptozotocin of 30mg/kg.Before modeling, insulin sensitivity index is calculated to determine whether insulin resistance. After modeling, rats were fed continue to 17 W. The surviving rats were randomly divided into model group(DM group, without drug treatment), metformin group(DMBG Group, metformin of 300mgkg·-1·d-1 orally treated 4w), Bevacizumab group(BEV Group, vitreous cavity injection of 100μmol/L Bevacizumab solution 5μl, and repeat the operation after three days), and the combined group(DMBG+BEV Group). General condition of rats was observed. Blood glucose was monitored regularly. Retinal permeability was detected by Evans blue(EB) method. Pathological changes were observed in rat retina using HE staining. Expression of VEGF and p AMPK was detected by immunohistochemistry and immunoblotting method, experimental data was analyzed using SPSS statistical software.Results After the high-fat diet 8W, model group rats body weight, fasting insulin levels were significantly higher than the control group(324.69 ± 23.13 vs268.07 ± 31.91,47.45 ± 7.86 vs 21.31 ± 3.42, P <0.01). Compared with normal control group, model group is no significant differences in fasting plasma glucose(5.80 ± 0.80 vs 5.63 ± 0.50), while and insulin sensitivity index was significantly lower(-5.59 ± 0.14 vs-4.77 ± 0.19, P <0.01). After the injection of STZ, compared with the normal control group, blood glucose was significantly higher in the model group and the majority of rats had cataract symptoms. Fasting blood glucose was significantly reduced in DMBG group and spiritual malaise situation of rats has improved; Compared with the DMl group, the difference was no significant in BEV rats, but the cataract symptoms has reduced. There was no significant difference between the combined treatment group and DMBG group, but cataract symptom was improved. After modeling 20 W, compared with the control group, EB infiltration capacity of other groups was significantly increased. Compared with DM group, the drug-treated groups showed EB infiltration capacity was reduced, which is the most significant in the combined treatment group. Pathological examination showed retinal tissue edema and disorders, telangiectasia in DM group. Compared with DM group, the treatment group showed significant improvement in lesions, particularly in the combined treatment group. Immunohistochemistry and western blot analysis showed: There is only a small amount of VEGF expression in CON group, mainly in the ganglion cell layer and inner nuclear layer. DM group showed significant expression of VEGF, almost all layers visible positive cells. Compared with DM group, VEGF expression in each treatment group was significantly reduced, especially combined treatment group decreased the most obvious. p AMPK expression is visible in a clear in CON group. There is a small amount expression in DM group. There is no difference for expression of p AMPK between BEV and DM group, but p AMPK expression of DMBG and the combination group was significantly enhanced.Conclusions Bevacizumab combined with metformin can reduce the degree of retinopathy in diabetic rats by inhibiting the expression of VEGF expression and activating p AMPK.