Therapeutic Effects And Mechanism Of Berberis Cortex Extract On Diabetic Retinopathy

ObjectiveIn present study,the effective part extract of a commonly used Tibetan herb Berberis Cortex extract, was selected as the research objiect.Firstly,the acute toxicity test in mice and the determination of some parameters witch related on rat liver and kidney function were conducted to provided scientific basis of safety and effectiveness for clinical use of Berberis Cortex extract.Then we evaluated the regulating effect of blood glucose levels,protection against oxidative stress,protection function on blood vessels and mechanism of DR rats with Berberis Cortex extract.MethodFirstly, the acute toxicity test in mice and the determination of some parameters witch related on rat liver and kidney function were conducted to valuated the security of Berberis Cortex extrac;Secondly,the protective effect of pathological changes on retina were observed by utilizing the diabetic retinopathy rats induced by streptozotocin (STZ);Thirdly, the The regulating effect with blood glucose levels of Berberis Cortex extract were observed by utilizing the following models:the Alloxan induction diabetes mice, diabetic retinopathy rats induced by streptozotocin (STZ) and normal mice;Finally, The NO, MDA and SOD levels of the diabetic retinopathy rats were measured to comment on the regulation of Berberis Cortex extract on oxidative stress. And the HIF, ICAM-1, VEGF, PKC and ANG II levels of the diabetic retinopathy rats were measured to evaluate the vascular protection mechanism of Berberis Cortex extract.ResultsFirstly,according to the results of the acute toxicity test in mice,the median lethal dose of Berbreis Cortex extract on mice was17.169g·kg-1,equivalent to206times of clinical dosage respectively.The liver and kidney function of rats were not damaged by Berberis Cortex extract.Secondly, Berberis Cortex extract could improve retinal tissue structure of DR model rats and Significantly reduced retinal capillary basement membrane thickness and retinal E/P value.Thirdly, Berberis Cortex extract could significantly decrease the fasting blood glucose of Alloxan induction diabetes mice and diabetic retinopathy rats induced by streptozotocin (STZ), however, the reducing sugar function of Berberis Cortex extract were not observed on normal mice;Finally, the regulation of Berberis Cortex extract on oxidative stress were observed in Berberis Cortex extract treated rats,which mainly manifested as decreasing the MDA and NO level while increasing the SOD level.The vascular protection mechanism of Berberis Cortex extract were observed in Berberis Cortex extract treated rats,which mainly manifested as decreasing the HIF,VEGF,PKC,ICAM-1and ANGⅡ level.ConclusionAll the data indicate that Berberis Cortex extract has an effective therapeutical action on DR,which may be related to three aspects as follows:Firstly, decreasing the fasting blood glucose; secondly, reducing the oxidative stressby means of decreasing the MDA and NO level while increasing the SOD level; finally, protecting the pathological changes on retinal by means of decreasing the HIF,VEGF,PKC,ICAM-1and ANG Ⅱ level.Based on these results, we believe that Berberis Cortex extract may be used as a potential Candidate drugs for the prevention and control of diabetic retinopathy.