Mating induces production of MMP2 in the llama oviduct: Analysis of MMP2 effect on semen

Ovulation of South American Camelids is induced by mating. After copulation, sperm are stored into the oviduct to be released near ovulation time. To study whether copulation induces matrix metalloproteinase-2 (MMP2) secretion in the oviduct, the occurrence of MMP2 in oviductal tissue and oviductal fluid (OF) from 24 h post-mated was compared with non-mated llama females. There was an incremental increase of MMP2 in the oviductal epithelial cells, and MMP2 activity in OF after copulation. Additionally, MMP2 activator (MMP14), inducer (EMMPRIN) and inhibitor (TIMP2) were present in the oviductal epithelial cells of both non-mated and post-mated females. A post-mating segment-specific regulation occurred because relative abundance of TIMP2 mRNA was greater in the utero tubal-junction which was accompanied with a reduced amount of MMP14 in the ampulla in comparison with the non-mated females. To examine the effect of MMP2 on semen liquefaction and sperm physiology, the effects of addition of recombinant human MMP2 was evaluated. The MMP2 had no effect on semen thread formation and seminal plasma protein profile. Sperm viability and plasma membrane function were not influenced by the enzyme treatment either. In summary, in llamas the oviductal microenvironment changes in response to stimuli induced by copulation, increasing the production and secretion of MMP2.