Effect of oxycodone on microglial activation in brain tissues of rats

Abstract

Objective To evaluate the effect of oxycodone on microglial activation in brain tissues of rats. Methods Primarily cultured microglial cells of Sprague-Dawley rats were seeded in 24-well plates(1 ml/well)at a density of 1×105 cells/ml and divided into 5 groups(n=40 each)using a random number table: control group(group C), lipopolysaccharide(LPS)group(group L)and low, medium and high concentrations of oxycodone groups(O25, O50, O100 groups). The cells were cultured in serum-free medium for 24 h in group C. LPS was added at the final concentration of 1 μg/ml in L, O25, O50 and O100 groups, and in addition oxycodone was added at the final concentration of 25, 50 and 100 ng/ml at 24 h of incubation with LPS in O25, O50 and O100 groups, respectively.Cells were collected at 1 h of incubation or culture for determination of the expression of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), IL-10 and transforming growth factor-1β(TGF-1β)mRNA(by real-time polymerase chain reaction)and expression of TGF-1β and phosphorylated Smad2(p-Smad2)(using Western blot). The concentrations of TNF-α, IL-1β and IL-10 in the supernatant were detected by enzyme-linked immunosorbent assay. Results Compared with group C, the expression of TGF-β1, IL-1β and TNF-α mRNA, TGF-β1 and p-Smad2 was significantly up-regulated, and the concentrations of IL-1β, IL-10 and TNF-α in the supernatant were increased in group L(P 0.05). Conclusion Oxycodone can inhibit microglial activation in brain tissues of rats. Key words: Oxycodone; Microglia; Brain