The protective effect of small peptides from Periplaneta americana on hydrogen peroxide–induced apoptosis of granular cells

Abstract

This study investigates the protective effect of small peptides from Periplaneta americana (SPPA) on hydrogen peroxide (H₂O₂)–induced apoptosis of ovarian granular cells. H₂O₂ was applied to human ovarian granular cells (KGN cell strains). Cell viability was tested by cell counting Kit-8 (CCK-8). Cell apoptosis was tested by flow cytometry, and a cell apoptosis model was established. The model cells were treated with SPPA, and the cell survival rate was monitored using the CCK-8 method. The oxidative stress state of cells was examined using SOD, ROS, MDA, and NO kits. The protein expression levels of SIRT1, p53, and the apoptosis-related gene Caspase3 were measured using Western Blot methodology. Relative to the control group, cell viability declined significantly after the H₂O₂ treatment only (P < 0.01), while the apoptosis rate increased significantly (P < 0.01). The activity of SOD was weakened significantly (P < 0.01), while the cell levels of ROS, MDA, and NO increased dramatically (P < 0.01). Cell viability dramatically recovered (P < 0.01), and the SOD activity is hugely increased (P < 0.01) after SPPA treatment. In contrast, contents of ROS, MDA, and NO decreased sharply (P < 0.01), and significant dose-response relationships are characterized. Moreover, the H₂O₂ treatment group showed significantly downregulated expression of SIRT1 (P < 0.01) but significantly upregulated expressions of p53 and Caspase3 (P < 0.01) compared to the control group. Following the SPPA treatment of apoptosis cells, expression of SIRT1 increased significantly, while expressions of p53 and Caspase3 declined significantly (P < 0.01). This study suggests that SPPA inhibits H₂O₂-induced human KGN cell apoptosis through antioxidation, and the SIRT1/p53 signal pathway mediates the antioxidation.