Abstract:
Objective To investigate the effects of sodium p-aminosalicylic acid (PAS-Na) on oxidative damage and inflammatory response of rat thalamic primary microglia induced by manganese.
Methods Purified and identified SD rat's thalamic microglia were cultured with different concentrations of MnCl2 (0, 200, 300, 400, and 500 μmol/L, respectively) and PAS-Na (50, 150, and 450 μmol/L, respectively) in complete mediums (DMEM+FBS) for 24 h. Cell viability was determined by MTT to identify a suitable dose of manganese exposure and non-toxic dose of PAS-Na exposure. Then cells were randomly divided into control group, 400 μmol/L MnCl2 group, 400 μmol/L MnCl2+PAS-Na (50, 150, and 450μmol/L, respectively) groups, and 450 μmol/L PAS-Na group. The survival rate of microglia in each group was detected by MTT assay. The level of intercellular reactive oxygen species (ROS) was detected under fluorescence inverse microscope with DCFH-DA probe mark. The protein expressions of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were detected by ELISA, and the mRNA expression levels of IL-1β and TNF-α were determined by RT-PCR.
Results The survival rates of cells treated with 400 and 500 μmol/L MnCl2 were (85.83±12.53)% and (83.30±6.33)%, respectively, lower than that of the control group (Ps < 0.05). Therefore, the exposure dose of 400μmol/L was chosen. Compared with the control group, the survival rates of the 50, 150, and 450 μmol/L PAS-Na groups did not change (Ps>0.05). The survival rates of the 400 μmol/L MnCl2+PAS-Na (50, 150, 450 μmol/L) groups were (96.00±18.11)%, (106.13±18.32)%, and (110.21±15.13)%, respectively, higher than that of the 400 μmol/L MnCl2 group (Ps < 0.05). Compared with the control group, the levels of ROS, the protein and mRNA expression levels of IL-1β and TNF-α in the 400 μmol/L MnCl2 group increased (Ps < 0.05). Compared with the 400 μmol/L MnCl2 group, the levels of ROS, protein expression levels of TNF-α, and the mRNA expression levels of IL-1β in the 400 μmol/L MnCl2+PAS-Na groups (50, 150, 450 μmol/L) decreased (Ps < 0.05), and the mRNA expression levels of TNF-α in the 400μmol/L MnCl2+PAS-Na groups(150, 450μmol/L) also decreased (Ps < 0.05).
Conclusion PAS-Na may alleviate the oxidative damage and inflammatory response of thalamic primary microglia in rats induced by manganese.