Brain nitric oxide synthase expression is enhanced in the human cervix in labor

OBJECTIVES: To determine whether brain nitric oxide synthase (bNOS) is expr essed in human cervix, define its localization, and examine the possibility that it contributes to the nitric oxide (NO) pool and has a role in human cervical ripening. METHODS: Human cervical biopsy, tissues were collected from four, groups: ( 1) nonpregnant patients, (2) term nonlabor (cesarean delivery) patients, (3 ) term labor patients with cesarean deliveries, and (4)term labor Patients (vaginal delivery). The mRNA expression was assessed using reverse-transcri bed polymerase chain reaction and in situ hybridization. The protein expres sion was determined using Western blot and its localization was shown using immunostaining. RESULTS: Both bNOS mRNA and protein are present in human cervical tissue. T hey were localized to stroma cells and epithelial cells by in situ hybridiz ation and immunostaining, bNOS protein expression in the labor group was si gnificantly higher than in the nonlabor group (P < .05). CONCLUSION: bNOS is expressed in the human cervix and enhanced expression i s observed in labor, suggesting its possible role in contributing to the NO pool in the human cervix, in cervical ripening, and in labor. Copyright (C ) 2001 by the Society for Gynecologic Investigation