Cytotoxic Responses and Apoptosis in Rat Kidney Epithelial Cells Exposed to Lead / 生物医学与环境科学（英文）

The toxic effects of lead on normal rat kidney epithelial cells (NRK cells) may occur via various pathways. However, the role of intrinsic mitochondrial pathway in Lead-induced apoptosis in NRK cells has not been investigated. The purpose of our study was to investigate cytotoxic responses and cell apoptosis mediated by lead in NRK cells. NRK cells were treated with different concentrations of Lead acetate for 12 h to determine the cytotoxicity of lead. Mitochondrial transmembrane potential was also analyzed using a fluorescence spectrophotometer. Moreover, the activities of caspase-3 and caspase-9 were detected in the presence of lead. Finally, the lead-induced cell apoptosis was evaluated by flow cytometry in the present of caspase inhibitors Z-VAD-FMK and Ac-LEHD-FMK, respectively. The results would contribute to clarify the role of Lead in proliferation and apoptosis of NRK cells, and help to understand the underlying mechanism responsible for lead-induced cell apoptosis.

Immunomodulatory effects of betulinic acid from the bark of white birch on mice

The objective of this study was to explore the immunomodulatory effects of betulinic acid (BA) extracted from the bark of white birch on mice. Female mice were orally administered BA for 14 days in doses of 0, 0.25, 0.5, and 1 mg/kg body weight. We found that BA significantly enhanced the thymus and spleen indices, and stimulated lymphocyte proliferation induced by Concanavalin A and lipopolysaccharide as shown by MTT assay. Flow cytometry revealed that BA increased the percentage of CD4+ cells in thymus as well as the percentage of CD19+ and the ratios of CD4+/CD8+ in spleen. BA increased the number of plaque-forming cell and macrophage phagocytic activity as indicated by a neutral red dye uptake assay, and the peritoneal macrophages levels of TNF-alpha were also increased. In contrast, serum levels of IgG and IgM and serum concentrations of IL-2 and IL-6 were significantly decreased in BA-treated mice compared to the control as assayed by haemagglutination tests and ELISA, respectively. Taken together, these results suggest that BA enhances mouse cellular immunity, humoral immunity, and activity of macrophages. Thus, BA is a potential immune stimulator and may strengthen the immune response of its host.