Protective functions of Lycium barbarum polysaccharides in H(2)O(2)-injured vascular endothelial cells through anti-oxidation and anti-apoptosis effects

Cell injury in the cardiovascular endothelia caused by oxidative stress is among the major inducers of endothelium dysfunction and serves an important role in initiating cardiovascular diseases (CVDs). Therefore, protecting and improving the normal function of endothelial cells are considered key measures against CVDs. As a traditional Chinese medicinal component, Lycium barbarum is regarded to have high medicinal value. The present study aimed to investigate the potential anti-apoptosis and anti-oxidation effects of Lycium barbarum polysaccharides (LBPs) on injured rat artery endothelial cells, to demonstrate the experimental and medicinal values of LBPs. In the present study, the aortic endothelial cells of rats were cultivated and randomly divided into five groups: A control group, H(2)O(2)-injured group (H(2)O(2) group), H(2)O(2)+LBPs (110 µg/ml) group (low-dose group, LT), H(2)O(2)+LBPs (220 µg/ml) group (medium-dose group, MT) and H(2)O(2)+LBPs (440 µg/ml) group (high-dose group, HT). Among these, the activity of superoxide dismutase (SOD), and the levels of malondialdehyde (MDA) and nitric oxide (NO) were detected by colorimetry. Additionally, the expression of B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax) were detected by western blotting. It was observed that SOD activity and NO content decreased while MDA content increased significantly in the H(2)O(2) group (P<0.05 vs. control); that SOD activity in the MT and HT group, and NO content in all three LBP groups were increased, while MDA content in the three LBP groups was decreased, compared with the H(2)O(2) group (all P<0.05); that Bcl-2 expression decreased significantly in the H(2)O(2) group while the expression of Bax increased significantly compared with the control group (both P<0.05); and that Bcl-2 expression in all three LBP groups increased, while Bax expression in the MT and HT groups decreased compared with the H(2)O(2) group (all P<0.05), with these altered Bax levels being statistically similar to those in the control group (P>0.05). On light microscopy, the cells in the control group exhibited spindle-shaped morphology, consistent sizes, defined boundaries, and distinct nuclei of equivalent sizes with round or oval morphology. Additionally, the chromatin in the nuclei was evenly distributed, and all cells were adhered in a paving-stone arrangement. Notably, only few cells died. Conversely, the cells in the H(2)O(2) group exhibited signs of damage and enlarged gaps, and focal cells died. In the HT group, the cells once again appeared adherent and exhibited similar morphological status to the normal cells. Overall, these results indicate that LBPs serve a protective role in oxidative-injured vascular endothelial cells through anti-apoptosis and anti-oxidation effects.