Downregulation of CD38, CD95, and PD-1 Expression in T Cells of Aging Mice by Intervention of Polygala fallax Hemsl

Institute of Biological Sciences, Central Mindanao University, Maramag, Bukinong Province, Central Mereo Island, Philippines

^* Corresponding author's e-mail: emmanuelpleano@gmail.com

Abstract

The immune system plays an essential role in aging. Polygala fallax Hemsl. (PFH) enhances the immune response and promotes immune function. The study aimed to investigate whether PFH had a positive effect on the immune function of aging mice to delay aging. Kunming mice were selected to establish an aging mouse model by intraperitoneal injection of D-galactose at 500 mg/kg/day for 6 weeks. Astragalus membranaceus, which has been used as one of the positive control groups. After modeling, A. membranaceus low, medium, and high doses of PFH were administered by gavage for 4 weeks, Serum superoxide dismutase (SOD) and malondialdehyde (MDA) levels were evaluated using enzyme-linked immunosorbent assay. Flow cytometry was used to determine T-cell subsets and the expression of CD38, CD95, and PD-1 in peripheral blood. Prism 9.5.1 statistical software for classification analysis was used with all data expressed in (^¯x ± s). One way ANOVA was further used to detect statistically significant differences between group. Results revealed that serum SOD activity was decreased and MDA content was elevated in the MODEL group compared with those in the CONTROL group. A. membranaceus and PFH increased SOD activity and decreased MDA content. Furthermore, the expression of CD38, CD95, and PD-1 in CD4+ and CD8+ T cells was increased in the MODEL group compared with those in the CONTROL group. CD38, CD95, and PD-1 expression decreasing trend after the administration of A. membranaceus and PFH. Among them, CD38, CD95, and PD-1 were the most significantly reduced in PFH-L group. It is therefore concluded that PFH had a positive effect on CD4+ and CD8+ T-cell function in aging mice, which could delay aging to a certain extent.