244. Effect of batimastat, a specific inhibitor of matrix metalloproteinases, on endometrial breakdown and repair in a mouse model

Abstract

Strong correlative evidence supports a role for matrix metalloproteinases (MMPs) in the tissue breakdown at menstruation. As menstruation occurs in very few species besides women, there is a lack of suitable and easily accessible animal models available to examine the functional significance of potential key mediators of this process. A mouse model of endometrial breakdown and repair has been developed,1 which morphologically resembles that of human endometrium at menstruation. Previous studies in our laboratory showed that the expression patterns of various MMPs in the mouse model closely resembled those seen in the human.2 Administration of doxycycline, a broad spectrum MMP inhibitor, decreased gelatinase activity, but had no effect on tissue breakdown in this model. The aim of the present study was to further examine the importance of MMPs in endometrial breakdown and repair via administration of batimistat, a highly potent and specific MMP inhibitor. Batimistat was administered I.P to mice 24 h prior to the expected time of endometrial breakdown. The efficacy of batimistat within the uterus was proven using in situ zymography, which identifies MMP activity (rather than latent forms). This demonstrated that batimistat was reaching its target organ and effectively inhibiting MMP activities (both gelatinase and collagenase). Examination of gross uterine morphology revealed no apparent difference between groups, with batimistat treated uteri displaying a similar extent of tissue breakdown and repair to their control counterparts. Measurement of the breaking down area compared to total endometrial area revealed no difference between control and batimistat treatment, with the breaking down areas being 69 ±13% and 72 ± 9.8% of total endometrial cross-sectional area respectively. There was likewise no effect on endometrial repair. The results of this study together with our previous study using doxycycline, indicate that MMPs are not the key mediators of endometrial breakdown in this model. (1)Shen et al. (2004) Reprod. Fert. Dev. 16(Suppl), A265, p. 97.(2)Brasted et al. (2003) Biol. Reprod. 69, 1273.