Figure 3

Effects of β-arrestin2 on remifentanil pretreatment of RAW264.7 cells viability and apoptosis induced by LPS. (A) The expression of β-arrestin2 mRNA was measured by RT-PCR, which revealed that β-arrestin2 mRNA decreased about 60% after transfected with β-arrestin2 siRNA. *P < 0.05 compared to control. (B) The expression of β-arrestin2 protein was measured by western blot, which revealed that β-arrestin2 protein decreased about 55% after transfected with β-arrestin2 siRNA. *P < 0.05 compared to control. (C) Cell viability increased by remifentanil (10 ng/ml) pretreatment, measured by WST-8 dye, whereas the effect was abolished when silencing β-arrestin2 expression with siRNA. (*P < 0.05 compared to LPS alone). (D,E) Cell apoptosis was assessed by Hoechst 33342 dye assay, the nuclei at the early stage of apoptosis displayed an increased brightness of chromatin stain. Cell apoptosis stimulated by LPS (1 μg/ml) was attenuated after remifentanil pretreatment, whereas the effect was blocked when silencing β-arrestin2 expression with siRNA. (magnification: 200×; *P < 0.05 compared to LPS alone). All the results were from at least three independent experiments.