The Thai Journal of Veterinary Medicine


Endometrial matrix metalloproteinases (MMPs) are extensively studied in humans. However, owing to thedistinct differences of the estrous cycle of bitches, the expression and activities of endometrial MMPs regulated by sexhormones should be significantly different. To understand the effect of sex hormones on the activity of MMPs, thisstudy investigates the activities of endometrial MMP-2 and MMP-9 during different phases of the estrous cycle inbitches through the use of gelatine zymography. Estradiol and progesterone concentrations were also determinedusing enzyme-linked fluorescent assay. The activities of the latent forms of both MMP-2 and -9 were significantlyhigher in metestrus (MP) and late diestrus phases (L-DP) than in anestrus (AP) and proestrus/estrus phases (EP)(p<0.05). Similarly, the activities of the active forms of both MMPs in L-DP were significantly higher than in the otherphases of the estrous cycle (p<0.05). Significant correlations were found between progesterone and the activities oflatent and active forms of MMP-9 during MP (r= -0.83, p<0.05 and r= 0.94, p<0.01, respectively). Considering ourresults, together with that of previous studies on the role of MMPs in the reproductive system, we hypothesize thatendometrial MMP-2 and MMP-9 play a key role in successful fertilization.

First Page


Last Page