Role of SIRT1/NF-κB signaling pathway in mild hypothermia-induced promotion of microglial polarization during oxygen-glucose deprivation and restoration / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of Sirtuin 1/nuclear factor κB (SIRT1/NF-κB) signaling pathway in mild hypothermia-induced promotion of microglial polarization during oxygen-glucose deprivation and restoration (OGD/R).Methods:The well-grown BV2 microglia were divided into 4 groups ( n=36 each) using the random number table method: control group (group C), OGD/R group (group O), mild hypothermia group (group M), and mild hypothermia+ SIRT1 specific inhibitor EX527 group (group ME). Cells in group C were commonly cultured without any treatment. Cells in group O were subjected to 3 h of OGD followed by 21 h of restoration of O 2-glucose supply at 37 ℃. Cells in group M were subjected to 3 h of OGD followed by 21 h of restoration of O 2-glucose supply at 33 ℃. Cells in group ME were co-cultured with inhibitor EX527 (final concentration 5 nmol/L) for 12 h in the medium before OGD/R, and the other procedures were conducted as previously described in group M. The cell survival rate was detected by CCK-8 assay. The levels of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and interleukin-10 (IL-10) in supernatant were detected by enzyme-linked immunosorbent assay. The expression of CD206, CD32, inducible nitric oxide synthase (iNOS) and arginine synthase 1 (Arg-1) mRNA was detected by quantitative real-time polymerase chain reaction. The expression of CD206 and CD32 was detected by immunofluorescent staining. The expression of iNOS, Arg-1, SIRT1, NF-κB p65 (p65) and acetylated NF-κB (Ac-p65) was detected by Western blot. Results:Compared with group C, the cell survival rate was significantly decreased, the concentrations of TNF-α, IL-6 and IL-10 in the supernatant were increased, the expression of CD206, Arg-1, CD32 and iNOS was up-regulated, the expression of SIRT1 was down-regulated, and the Ac-p65/p65 ratio was increased in group O ( P<0.05). Compared with group O, the cell survival rate was significantly increased, the concentrations of TNF-α and IL-6 in the supernatant were decreased, the concentration of IL-10 was increased, the expression of CD206, Arg-1 and SIRT1 was up-regulated, the expression of CD32 and iNOS was down-regulated, and the Ac-p65/p65 ratio was decreased in group M ( P<0.05). Compared with group M, the cell survival rate was significantly decreased, the concentrations of TNF-α and IL-6 in the supernatant were increased, the concentration of IL-10 was decreased, the expression of CD206, Arg-1 and SIRT1 was down-regulated, the expression of CD32 and iNOS was up-regulated, and the Ac-p65/p65 ratio was increased in group ME ( P<0.05). Conclusions:SIRT1/NF-κB signaling pathway is involved in mild hypothermia-induced promotion of microglial polarization during OGD/R.