Role of RhoA/ROCK2 signaling pathway in propofol-induced neuroapoptosis in hippocampus of newborn rats

Abstract

Objective To evaluate the role of Ras homolog family member A (RhoA)/Rho-associated coiled-coil containing protein kinase 2 (ROCK2) signaling pathway in propofol-induced neuroapoptosis in the hippocampus of newborn rats. Methods ExperimentⅠ Primarily cultured hippocampal neurons were seeded in 6-well culture plates at a density of 1×106 cells/ml and divided into 2 groups (n=6 each) using a random number table: solvent control group (C group) and propofol group (P group). Propofol was added with the final concentration of 60 μg/ml in group P. Dimethyl sulfoxide was added with the final concentration of 0.04% in group C. The expression of RhoA and ROCK2 in hippocampal neurons was measured by Western blot at 24 h of incubation.ExperimentⅡ Primarily cultured hippocampal neurons were seeded in 6-well culture plates at a density of 1×106 cells/ml and divided into 3 groups (n=6 each) using a random number table: solvent control group (C group), propofol group (P group) and propofol plus specific RhoA/ROCK2 signaling pathway blocker Y27632 group (P+ Y group). Propofol was added with the final concentration of 60 μg/ml in group P. Propofol at the final concentration of 60 μg/ml and Y27632 at the final concentration of 10 μmol/L were added in group P+ Y.Dimethyl sulfoxide was added with the final concentration of 0.04% in group C. At 24 h of incubation, the neuroapoptosis in hippocampi was detected by flow cytometry, and the expression of activated caspase-3 in hippocampal neurons was measured by Western blot.The apoptotic rate was calculated. Results ExperimentⅠ Compared with group C, the expression of RhoA and ROCK2 in hippocampal neurons was significantly up-regulated in group P (P<0.05). Experiment Ⅱ Compared with group C, the apoptotic rate of hippocampal neurons was significantly increased, and the expression of activated caspase-3 was up-regulated in P and P+ Y groups (P<0.05 or 0.01). Compared with group P, the apoptotic rate of hippocampal neurons was significantly decreased, and the expression of activated caspase-3 was down-regulated in group P+ Y (P<0.05). Conclusion Activation of RhoA/ROCK2 signaling pathway is involved in propofol-induced neuroapoptosis in hippocampi of newborn rats. Key words: Rho factor; Rho-associated kinases; Propofol; Infant, newborn; Apoptosis; Hippocampus; Neurons