Conditional deletion of the relaxin receptor gene in cells of smooth muscle lineage affects lower reproductive tract in pregnant XXXX .

@entity19 @entity57639 @entity21823 @entity25325
Relaxin hormone secreted into the circulation during pregnancy was discovered through its effects on pubic symphysis relaxation and parturition. Genetic inactivation of the relaxin gene or its cognate @entity57639 ( @entity57639 ) in @entity19 caused failure of parturition and mammary nipple enlargement, as well as increased collagen fiber density in the cervix and vagina. However, the relaxin effect on discrete cells and tissues has yet to be determined. Using @entity19 with a knockin LacZ reporter in the @entity57639 allele, we showed strong expression of this gene in vaginal and cervical stromal cells, as well as pubic ligament cells. We produced a floxed @entity57639 allele that was used in combination with the @entity21823 -cre transgene to generate @entity19 with a smooth muscle-specific gene knockout. In pregnant females, the @entity25325 reporter activated by @entity21823 -cre was detected in smooth muscle cells of the cervix, vagina, uterine artery, and in cells of the pubic symphysis. In late pregnant females with conditional gene ablation, the length of pubic symphysis was significantly reduced compared with wild-type or heterozygous @entity57639 (+/-) females. Denser collagen content was revealed by Masson trichrome staining in reproductive tract organs, uterine artery, and pubic symphysis. The cervical and vaginal epithelium was less developed than in heterozygous or wild-type females, although nipple size was normal and the dams were able to nurse their pups. In summary, our data indicate that relaxin/ @entity57639 signaling in smooth muscle cells is important for normal collagen turnover and relaxation of the pubic symphysis during pregnancy.
