Expression of gelatinases and tissue inhibitors of metalloproteinases in the rhesus monkey (Macaca mulatta) corpus luteum

Abstract

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are believed to play important roles in the formation and regression of corpus luteum (CL). This study is to investigate the expression of gelatinases (MMP-2, -9) and TIMPs in the rhesus monkey CL in both early and late luteal phases and during the early stages of pregnancy. Ovaries were collected from regularly cycling rhesus monkey at D5 and D15 following ovulation and at D12, D18 and D26 of pregnancy.In situ hybridization revealed that in the CL MMP-2 mRNA was expressed during both formation and regression, while MMP-9 mRNA was mainly localized in the late luteal phase. Reduction of MMP-2, -9 transcripts in the CL was observed during pregnancy. MMP-2 mRNA in the CL reduced to an undetectable level at D26 of pregnancy. TIMP-1 mRNA was highly expressed in the CL in both early and late luteal phases and persisted throughout the early stages of pregnancy. Strong signal for TIMP-2 mRNA was also detected in both luteal phases, and the level of TIMP-2 mRNA gradually increased with the progresses of pregnancy. No TIMP-3 mRNA was detected in the macaque CL in this study. In conclusion, these results suggest that MMP-2, -9 and TIMP-1, -2 may have functional roles in rhesus monkey CL. Coordinated expression of MMP-2, -9 and TIMP-2 may play a role in the maintaining of luteal function during early pregnancy. The unchanged expression pattern of TIMP-1 indicates that it may have other functions in the primate CL than inhibition of MMPs.