Research Progress in Effects of Matrix Metalloproteinases MMP2 and MMP 9 on Follicular Development in Mammals

In mammalian follicular development, it is accompanied by significant tissue remodeling, which includes follicular cavity formation and expansion, ovulation, luteinization and atresia. In the extracellular matrix（ECM）and follicular fluid derived from follicular membrane cells and granulosa cells, there are abundant proteins such as gelatin protein, fibrin and type Ⅳ collagen. These active proteins provide necessary conditions for the migration, proliferation and differentiation of follicular membrane cells and granulosa cells. Under the coordination control of the other MMPs, estrogen, apoptosis and autophagy signaling pathways, MMP2 and MMP9 decompose proteins such as gelatin protein, fibrin and type Ⅳ collagen in extracellular matrix and follicular fluid, promote cell apoptosis and angiogenesis, degrade and reshape ovarian tissues, and then affect the function of follicular membrane cells and granulosa cells, the formation and expansion of follicular cavity, and regulate the growth and development of follicles. This paper mainly reviews the research progress of MMP2 and MMP9 in regulation of follicular growth, ovulation, luteinization and atresia.