Myometrial apoptosis: activation of the caspase cascade in the pregnant rat myometrium at midgestation.

In the present study, we determined the contribution of myometrial hyperplasia, hypertrophy, and apoptosis to uterine growth during pregnancy. The changes in two endogenous markers of cell replication, proliferating cell nuclear antigen (PCNA) protein expression and bromodeoxyuridine (BrdU) incorporation, were studied. Myocyte hypertrophy was assessed by measuring the protein:DNA ratio.

Mitogen-activated protein kinases mediate stretch-induced c-fos mRNA expression in myometrial smooth muscle cells.

Evidence indicates that stretch of the uterus imposed by the growing fetus contributes to the onset of labor. Previously we have shown that mechanically stretching rat myometrial smooth muscle cells (SMCs) induces c-fos expression. To investigate this stretch-induced signaling, we examined the involvement of the mitogen-activated protein kinase (MAPK) family.

Regulation of c-fos expression by static stretch in rat myometrial smooth muscle cells.

Objective: We investigated whether mechanical stretch stimulates expression of the immediate early gene c-fos messenger RNA in rat myometrial smooth muscle cells.

Study Design: Freshly isolated myometrial smooth muscle cells (from virgin rats) were plated on flexible culture plates that were coated with either collagen I, laminin, elastin, or pronectin and were subjected to a static stretch with a computerized strain unit. Immunocytochemistry was used to define smooth muscle cell phenotype, and c-fos expression levels were assessed by Northern blotting.