Abstract:Objective To investigate the effects of Mingmu Dihuang Pills on autophagy and Akt-mTOR signaling pathway in retinal tissue of diabetic retinopathy (DR) rats. Methods The DR rat model was prepared by high fat and high sugar feed combined with intraperitoneal injection of Streptozotocin (40 mg/kg) method, and they were divided into model group, Calcium Dobesilate group (150 mg/kg), low (150 mg/kg), medium (300 mg/kg), high (600 mg/kg) dose of Mingmu Dihuang Pills groups by random number table method, with 10 rats in each group, and 10 rats were selected as normal control group, all the rats were given the medicine continuously for 10 weeks, the weight and blood sugar of the rats in each group were monitored. After 10 weeks of administration, the number of autophagic corpuscles in the retinal tissue was observed by transmission electron microscope; Western blot was used to detect autophagy related protein Beclin1, microtubule associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ), Akt, p-Akt, mTOR and p-mTOR protein in retinal tissue. Results Compared with the normal control group, the retina tissue of rats in the model group showed the changes of vacuoles, the cells arranged sparsely and disorder and so on, the number of autophagic corpuscles decreased significantly (P < 0.05), the expression of Beclin and LC3-Ⅱ protein was obviously down-regulated (P < 0.05), the expression of p-Akt and p-mTOR protein was significantly up-regulated (P < 0.05); compared with the model group, the pathological changes of rats retina tissue in the low, medium and high dose of Mingmu Dihuang Pills groups were significantly improved (P < 0.05), the number of autophagic corpuscles increased significantly (P < 0.05), the expression of Beclin and LC3-Ⅱ protein was significantly up-regulated (P < 0.05), the expression of p-Akt and p-mTOR protein was obviously down-regulated (P < 0.05), in dose-dependent manners. Conclusion Mingmu Dihuang Pills can inhibit the process of autophagy in retinal tissue of diabetic retinopathy rats, and its mechanism may be achieved by the regulating the expression of autophagy related proteins through the Akt-mTOR signaling pathway.
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