The effect of lactation in the post-partum arthritis of MRL-lpr/fas mice

Objective. To investigate the effects of lactation on the post-partum arthritic hare in MRL-lpr/fas mice. Methods. Three groups of mice were investigated. Group I: females whose litters were weaned at termination of the experiment; group 2: females whose litters were weaned at parturition; group 3. females who were not bred. Clinical evaluation was carried out at 5-day intervals following parturition. Blood samples were also collected during the course of the experiment and assayed for corticosterone and prolactin, Histological evaluation of the joints was assessed at day 30. Results. The incidence of swelling and erythema, the bimalleolar ankle width and the histopathology were significantly reduced by removal of the litters at parturition. This correlated well with a decrease seen in prolactin levels in these females. Corticosterone. an immunomodulatory glucocorticoid, did not play a significant role in the arthritic flare. Conclusion. Our findings suggest that prolactin levels contribute to the inflammation seen in MRL-lpr/fas mice following parturition.