Correlation between expression of RhoA and Rho kinase in uterine smooth muscle and the onset of labor

Abstract

To investigate the role of RhoA and Rho kinase system in the onset of labor. Forty term pregnant women, who delivered through cesarean section at the Xiangya Second Hospital of Central South University from February 2007 to November 2007, were selected and divided into 2 groups: 20 in labor group and 20 in non-labor group. Another 20 non-pregnant women undergoing hysterectomy due to cervical intraepithelial neoplasia were chosen as the control. Real-time fluorescence quantitative RT-PCR and western blot were applied to detect the expression RhoA and ROCK I mRNA and protein in uterine smooth muscle tissue and the correlation between the mRNA and protein expression of RhoA and ROCK I were analyzed. (1) The mRNA expressions of both RhoA and ROCK I were detected in all groups, and higher levels were found in the labor group than in the non-labor group and the control [RhoA mRNA: (3.51 +/- 0.56) x 10(-3) vs. (2.75 +/- 0.52) x 10(-3) and (2.11 +/- 0.54) x 10(-3); ROCK I mRNA: (4.07 +/- 0.66) x 10(-3) vs. (2.71 +/- 0.52) x 10(-3) and (2.01 +/- 0.23) x 10(-3), P < 0.01]. (2) RhoA and ROCK I proteins were also identified in all three groups, and the expressions in the labor and non-labor group were higher than those of the control (RhoA protein: 0.72 +/- 0.23 and 0.64 +/- 0.17 vs. 0.46 +/- 0.15; ROCK I protein: 0.56 +/- 0.14 and 0.42 +/- 0.16 vs. 0.29 +/- 0.08, P < 0.01). (3) The expression of RhoA mRNA and ROCK I mRNA were positively correlated in each of the three groups (r = 0.73, P < 0.01), and the same was found in the expression of RhoA protein and ROCKI protein (r = 0.37, P < 0.01). The increased expression of RhoA and Rho kinase may play an important role in the initiation of labor.