Effect of lactation on postpartum uterine involution in rat

To see the effect of lactation on uterine involution. Setting: Postgraduate Medical Institute, Lahore. Design: Study of uterine weight and extracellular matrix in rat uterine wall. Subjects: Sixty six mature virgin albino rats. Average age 8 weeks. Average weight 156gms. Group A [non pregnant] 06 animals. Group B [postpartum lactating] 30 animals. Group C [postpartum non lactating] 30 animals. Six animals from group B and C each sacrificed daily from day 1-5 after parturition. Uterine weight increased 10-11 folds on first day after parturition [P <0.01]. The uterine wall was thickened. The collagen fibres were increased through out the uterine wall. They were surrounding groups of muscle fibres and individual myocytes also. Collagen degradation and removal resulted in uterine involution which was accelerated by lactation. Lactation accelerates the process of uterine involution

Changes in extracellular matrix in rat uterine wall during pregnancy

To find changes in collagen fibers in extracellular matrix of uterine wall during early and late pregnancy. Settings: Postgraduate Medical Institute, Lahore. Design: Study of extracellular matrix in rat uterine wall. Subjects: Twenty four virgin mature albino rats. Average age 08 weeks. Average weight 155gms. Group A [non pregnant [06 animals. Group B [Pregnant] 18 animals, sacrificed after 1st, and 2nd and 3rd week of pregnancy. A significant rise in the uterine weight [without fetuses] during pregnancy was observed. During early pregnancy the collagen fibres were increased. Collagen degradation was noted during late pregnancy, which was correlated to increased amount of ground substance between the fibers. Thickness of uterine wall increased significant during early pregnancy but at full term it thinned out due to great stretching of the wall. During early pregnancy collagen fibres are increased in extracellular matrix of rat uterine wall, while, during late pregnancy they show degradation