目的：探讨蒲黄提取物对糖尿病视网膜病变(DR)大鼠的保护作用。

方法：将50只SPF级大鼠随机分为对照组：正常饲养； DR组：给予等量的生理盐水灌胃； 实验A组：蒲黄提取物50mg/(kg·d)； 实验B组：蒲黄提取物100mg/(kg·d)； 实验C组：蒲黄提取物200mg/(kg·d)。测定各组大鼠空腹血糖； HE染色观察各组大鼠视网膜病理学变化； ELISA检测各组大鼠血清中IL-6、TNF-α含量； Western blot检测视网膜组织VEGF、VEGFR2和Ang-1蛋白表达水平； qRT-PCR法检测视网膜组织VEGF、VEGFR2和Ang-1 mRNA表达水平。

结果：与对照组相比，DR组和各实验组大鼠空腹血糖、血清中IL-6、TNF-α含量及视网膜组织VEGF、VEGFR2和Ang-1的蛋白及mRNA表达水平均显著升高(P<0.05)； 与DR组相比，各实验组大鼠空腹血糖均有下降，且实验B组和实验C组大鼠空腹血糖显著降低(P<0.05)； 此外，实验B组和实验C组大鼠血清中IL-6、TNF-α含量、视网膜组织VEGF、VEGFR2和Ang-1的蛋白及mRNA表达水平与DR组相比均降低(P<0.05)。HE结果发现，DR组大鼠视网膜光感受器细胞层结构被明显破坏，细胞出现水肿、间隙增宽； 实验B组和实验C组大鼠视网膜组织病理学均有不同程度改善。

结论：蒲黄提取物可下调DR大鼠炎症水平及VEGF、VEGFR2和Ang-1的表达，从而改善视网膜组织病变。

METHODS: Fifty SPF rats were randomly divided into five groups: control group with normal feeding, DR group was given the same amount of normal saline by gavage, experimental group A with Pollen Typhae extract 50mg/(kg·d), experimental group B with Pollen Typhae extract 100mg/(kg·d)and experimental group C with Pollen Typhae extract 200mg/(kg·d). Determination of fasting blood glucose in rats of each group. HE staining was used to observe the pathological changes of retina of rats in each group. The expression of IL-6 and TNF-α in the serum of rats were measured by ELISA. The VEGF, VEGFR2 and Ang-1 protein expression in retina tissue were observed by Western blot. The VEGF, VEGFR2 and Ang-1 mRNA expression in retinal tissue were observed by qRT-PCR.

RESULTS: Compared with the control group, the fasting blood glucose, the expression of IL-6 and TNF-α in serum and VEGF, VEGFR2 and Ang-1 protein and mRNA expression in retina tissue in DR group and each experimental group were significantly higher(P<0.05). Compared with DR group, fasting blood glucose decreased in all experimental groups, and the fasting blood glucose of experimental groups B and C was significantly decreased than that of DR group(P<0.05). In addition, the contents of IL-6 and TNF-α in serum, the protein and mRNA expression levels of VEGF, VEGFR2 and Ang-1 in retina tissue in experimental group B and group C were significantly lower than those in group DR(P<0.05). The results of HE showed that the structure of retinal photoreceptor cell layer in DR group was obviously destroyed, the cell edema and gap widened, and the retinal histopathology of rat retina in group B and group C were improved in varying degrees.

CONCLUSION: Pollen Typhae extract can down-regulate the level of inflammation and the expression of VEGF, VEGFR2 and Ang-1 in DR rats, so as to improve the retinopathy.