藏药小檗皮对糖尿病大鼠视网膜PKC-β、VEGF、HIF-1α表达的影响

Effect of Tibetan Medicine Berberis Cortex on Expressions of PKC-β, VEGF, HIF-1α in Retina of Diabetic Rats

目的:探讨藏药小檗皮对糖尿病大鼠视网膜蛋白激酶C(PKC-β)、血管内皮细胞生长因子(VEGF)和低氧诱导因子(HIF-1α)的影响。方法:SD大鼠采用链脲佐菌素(STZ)一次性腹腔内注射的方法造模,随机分为模型组、小檗皮低剂量、中剂量和高剂量组、二甲双胍组、羟苯磺酸钙组、小檗碱组和对照组。成模后开始灌胃给药,小檗皮低剂量组、中剂量组、高剂量组分别按成人剂量的5、10、20倍给药,二甲双胍组和小檗碱组按成人剂量的10倍给药,模型组和对照组予灌服蒸馏水。所有实验大鼠于灌胃6周后处死。采用实时荧光定量PCR和Western Blot检测视网膜PKC-β、VEGF和HIF-1α表达,采用免疫组织化学法检测视网膜HIF-1α蛋白表达。结果:与正常组比较,糖尿病大鼠视网膜中PKC-β、VEGF、HIF-1αmRNA和蛋白表达显著升高(P<0.01);与模型组比较,小檗皮高、中剂量组视网膜PKC-β、VEGF和HIF-1αmRNA表达显著降低(P<0.01),PKC-β、VEGF和HIF-1α蛋白表达水平明显降低(P<0.05),小檗皮低剂量组大鼠PKC、VEGF和HIF-1α表达明显降低(P<0.05)。结论:小檗皮对糖尿病大鼠视网膜具有保护作用,其作用机制可能与整体多点调控糖尿病大鼠视网膜的PKC-β、VEGF、HIF-1α表达有关。

This study was aimed to investigate the effects of extract from Tibetan medicine Berberis Cortex （TMBC） on expressions of protein kinase C （PKC-β）, vascular endothelial growth factor （VEGF） and hypoxia-inducible factor （HIF-1α） in the retina of diabetic rats. Diabetic rats were established by one time intraperitoneal injection of strepto-zocin （STZ）. Rats were randomly divided into the model group, low-dose TMBC group, medium-dose TMBC group, high-dose TMBC group, metformin group, calcium dobesilate group, berberine group and the normal control group. Intragastric administration was given. The medication amounts of TMBC in the low-dose, medium-dose and high-dose group were 5, 10, and 20 times to the adult medication dose. In the metformin group and the berberine group, 10 times of the adult medication dose were given. Distilled water was given in the model group and the normal con-trol group. After 6-week intragastric administration, all experimental rats were sacrificed. The expressions of PKC-β, VEGF and HIF-1α were examined by real-time fluorescence quantitative PCR assay and western blot. HIF-1α ex-pression was detected by immunohistochemistry. The results showed that compared with the normal control group, the mRNA and protein expression of PKC-β, VEGF and HIF-1α increased obviously in the retina of diabetic rats （ P〈0.01）. Compared with the model group, the mRNA expression of PKC-β, VEGF and HIF-1α in the high-dose and medium-dose TMBC group reduced obviously （P〉.01）. The protein expression levels of PKC-β, VEGF and HIF-1α were also obviously reduced （P〉.05）. The expressions of PKC-β, VEGF and HIF-1α in the low-dose TMBC group were obviously reduced （P 〉.05）. It was concluded that TMBC can depress the expressions of HIF-1α, PKC-β and VEGF in the retina of diabetic rats, which can be served as a protective effect to prevent progress of di-abetic retinopathy.