Protective effects of Toona sinensis leaf extract on retinal tissue in rats with hyperlipidemia / 眼科新进展

ABSTRACT

Objective To investigate the protective effects of Toona sinensis leaf extract on the retina of rats with high-fat diet and the expression of B-cell lymphoma (Bcl-2) and Bcl-2 associated x protein (Bax).Methods Together 24 male SD rats were randomly divided into normal group (N group),hyperlipidemia model group (HF group) and hyperlipidemia model + toona sinensis leaf extract (HF + TSLE group),and then hyperlipidemia model was induced by fed high-fat diet in the latter two groups;after 8 weeks,the model was confirmed to be successful,and the rats in HF + TSLE group were fed with TSLE solution for 4 weeks continuously,and rats in N group and HF group were given the same dose of physiological saline.At the end of the twelfth week,all rats were followed by the examination of flash electroretinogram (FERG),serum lipid total cholesterol (TC),triglyceride (TG),low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C).Then,HE staining was performed in the retinas,the expression of Bcl-2 and Bax was detected by immunohistochemistry and Western blotting for the analysis of the correlation between the expression level of apoptotic protein Bax and the abnormal function of FERG.Results In HF group,the content of HDL-C decreased,and the contents of TC,TG and LDL-C were higher than those in N group,and the differences were statistically significant (all P ＜ 0.05).The contents of TC,TG and LDL-C in HF + TSLE group were lower than those in HF group,but the content of HDL-C was significantly increased,and the differences were statistically significant (all P ＜ 0.05).The content of HDL-C in HF + TSLE group was lower than that in N group,while the contents of TC,TG and LDL-C were higher than those in N group,and the differences were not statistically significant (all P ＞0.05).The difference of a wave latency between the three groups was statistically significant (P ＜ 0.05),and the latency of a wave in HF group was longer than that in N group,while HF + TSLE group was shorter than HF group,and the difference was statistically significant (P ＜ 0.05),but HF + TSLE group was longer than N group,and the difference was not statistically significant (P ＞ 0.05).Moreover,there was no significant difference in the incubation period of b wave in the three groups (P ＞ 0.05);and there was no significant difference in the amplitude of a wave and b wave in the three groups (all P ＞ 0.05).In addition,HF group had lower expression level of Bcl-2 and overexpression of Bax than N group.The expression level of Bcl-2 increased and Bax expression level decreased significantly in HF + TSLE group,and the expression level of Bax was positively correlated with the latency of a wave and b wave (all P ＜ 0.05),but was not correlated with amplitude of a wave and b wave (all P ＞ 0.05).Conclusion TSLE has an important role in the retina of rats with abnormal lipid metabolism,and it may play a protective role by regulating the expression of Bcl-2 and Bax.