Protective Mechanism of Lycium barbarum Polysaccharide (LBP) on H2O2-Induced Apoptosis of Human Epithelium Retinal Pigment Cells

Abstract

Lycii fructus boasts a rich heritage of medicinal usage in China. Lycium barbarum polysaccharide (LBP) has demonstrated a diverse range of biological effects, such as eye protection, anti-aging, anti-oxidation, regulating the immune system, nerve protection, cell protection and anti-tumor properties. However, there is limited research regarding the potential of LBP to protect human RPE cells from apoptotic cell death induced by hydrogen peroxide (H2O2). The study aims to examine how LBP protects human RPE cells from apoptotic induced by H2O2. The oxidative damage model of RPE cells induced by H2O2 was established, and then investigate the impact of LBP at 10 μmol/L and 100 μmol/L on the RPE activity, the proportion of apoptotic cells and the apoptotic-relevant proteins expression under the action of H2O2. RPE cells were divided into four groups: blank control group (AG), oxidant damage group (OG), low concentration of LBP group (GL, 10 μmol/L LBP), high concentration of LBP group (GH, 100 μmol/L LBP). The findings revealed that compared to the AG group, the cell survivorship decreased in the OG group, but increased following intervention by different concentrations of LBP, indicating a substantial difference (P <0.05). The apoptosis results indicated a significant increase in the OG in opposition to the AG (P < 0.05). When comparing the GH to the GL, there was a downward trend in the apoptotic rate (P < 0.05). In comparison to GL group, the apoptosis rate of GH showed a downward trend (P < 0.05). Furthermore, the Bax protein and Caspase-3 expression increased, while Bcl-2 expression decreased significantly in the OG group compared to the AG (P <0.01). Both the GL and GH groups showed a decrease in the Bax protein and Caspase-3, while BCL-2 increased significantly when opposed to the OG (P <0.01). The GH group demonstrated a downward trend in the Bax and Caspase-3, while the Bcl-2 protein showed an upward trend (P <0.05). Compared to the AG group, the OG demonstrated a decrease in Bcl-2 mRNA and an increase in Bax mRNA expression. The GL group showed higher Bcl-2 mRNA and lower Bax mRNA expression compared to the OG group. The GH group exhibited mRNA levels of Bcl-2 and Bax that were between the OG and GL groups (P <0.05). These findings suggest that LBP can prevent H2O2-induced apoptosis of RPE cells and holds potential value in the treatment of dry AMD.