The corpus luteum(CL)is a transient endocrine organ that secretes progesterone to support early pregnancy.If implantation is unsuccessful,luteolysis is initiated.Extensive tissue re-modeling occurs during CL formation and luteolysis.In this study,we have studied the possible in-volvement of MMP-2,-9,-14,and their inhibitors,TIMP-1,-2,-3 in the CL of cycling rhesus monkey at various stages by in situ hybridization,immunohistochemistry and microscopic assessment.The re-sults showed that the MMP-2 mRNA and protein were mainly expressed in the endothelial cells at the early and middle stages of the CL development,while their expressions were observed in the luteal cells at the late stage during luteal regression.MMP-9 protein was detected in the CL at the early and middle stages,and obviously increased at the late stage.The expressions of MMP-14 and TIMP-1 mRNA were high at the early and late stages,and low at the middle stage.TIMP-2 mRNA was high throughout all the stages,the highest level could be observed at the late stage.The TIMP-3 produc-tion was detected throughout all the stages,but obviously declined during CL regression.MMP-9,-14 and TIMP-1,-2,-3 were mainly localized in the cytoplasm of the steroidogenic cells.The results suggest that the MMP/TIMP system is involved in regulation of CL development in the primate,and the coordinated expression of MMP-2,-14 and TIMP-1,-3 may have a potential role in the CL forma-tion and the functional maintaining,while the interaction of MMP-2,-9,-14 and TIMP-1,-2,-3 might also play a role in CL regression at the late stage of CL development in the primate.
Embryo in uterine implantation is a complex and multifactor-related process and is a downstream and ideal point for woman fertility control. Understanding the cellular and molecular mechanism of implantation is a prerequisite for development of anti-implantation contraceptives. In spite of considerable accumulation of information from the laboratory animals that has been achieved, it is difficult to generate such information in human due to ethical restriction and experimental limitation, and the present knowledge for understanding the definitive mechanisms which control these events remains elusive. Embryo implantation can also occur outside uterus. Some women with abdominal pregnancies could successfully complete the processes of gestation and bear normal babies, implying that implantation itself may be not an endometrium-specific process. Reproductive biologists should cooperate with gynecologists to further comparatively study the molecular and cellular mechanisms of implantation normally occurring in endometrium and abnormally appearing outside uterine cavity. Such collaborative studies may generate new important information for developing anti-implantation contraceptive and for techniques of accurate diagnosis of ectopic pregnancy. A specially designed GnRH-2 analog and a combination use of low dose RU486 and gossypol as anti-implantation contraceptives have been suggested. Keywords embryo implantation - implantation window - materno-embryonic dialogue - ectopic pregnancy
