Response of the matrix metalloproteinase system of the chicken ovary to prolactin treatment.

The expression and activity of several matrix metalloproteinases (MMPs) has been demonstrated in the chicken ovary during various physiological states; these data indicate that MMPs are involved in the remodeling of the extracellular matrix (ECM) during follicle development, ovulation, atresia, and regression. The regulation of MMPs in the avian ovary, however, remains largely unknown. The present study aimed to examine the effect of recombinant chicken prolactin (chPRL) treatment on the expression of selected MMPs and their tissue inhibitors (TIMPs), as well as MMP-2 and MMP-9 activity in the hen ovary. Real-time polymerase chain reaction revealed changes in the mRNA expression of MMP-2, MMP-7, MMP-9, MMP-10, MMP-13, TIMP-2, and TIMP-3 in the following ovarian follicles: white, yellowish, small yellow, and the largest yellow preovulatory (F3-F1). Western blot analysis showed alterations in the abundance of latent and active forms of the MMP-2 protein, as well as the abundance of the MMP-9 protein. Moreover, minor changes in MMP-2 and MMP-9 total activities were found in ovarian follicles of chPRL-treated hens. The response to chPRL treatment depended upon the stage of follicle development, the layer of follicular wall, and the type of MMPs or TIMPs studied. In general, the results indicate that chPRL, is a positive regulator of MMP expression in the yellow preovulatory follicles. Our findings suggest that PRL participates in the mechanisms orchestrating ECM turnover during ovarian follicular development in the hen ovary via regulating the transcription, translation, and/or activity of some constituents of the MMP system.