Hormone-sensitive Lipase Lack Of Cell Biological Mechanisms Cause Infertility In Male Mice

HSL is present in adipose tissue, steroid hormones-forming tissue, mammary gland, skeletal muscle and monocyte/macrophage. It is mainly expressed in lipocyte. It can catalyze the hydrolysis of triglycerides as well as some fatsoluble or water-soluble substrate, and is thought to be a rate-limiting enzyme for the mobilization of fat in adipose tissue. Therefore, the HSL plays an important role in lipid and energy metabolism.A 120kDa new isoform of HSL which is present in testis has been described. Many research about HSL-deficient mice have been performed to understand the mechanisms. The results showed that the male HSL-deficient mice are infertile. These mice have decreased testis weights and testicular abnormalities, including the presence of multinucleated round and elongating spermatids, vacuolization of the seminiferous epithelium, asynchronization of the spermatogenic cycle, and a marked reduction in the numbers of late spermatids. These results show that HSL play an important role in spermatogenesis. The lack of HSL has an effect on the spermatogenesis and leads to the infertility of male.There are three types of cells which have the function of procreation in testis, they are Leydig cell, Sertoli cell and spermatogonia. Normally, HSL acts on some cells in testis to maintain physiological function of testis and produce sperm. The reason that HSL-deficient mice are infertile is not because of androgen change, therefore, ruling out the participation of Leyidg cells. What types of cells have been influenced by HSL is not clear.In physiological condition, it is imposible to observe the effect of absence of HSL because of the close relationship between Sertoli cells and spermatogonia. Transplantation technique of spermatogonial stem cells (SSC) provides us a useful tool to reconstruct different testicular cells in testis in vivo artificially. This technique was developed by Brinster in 1994, and now it is worked up.There are two parts in the research: 1. Donor SSC from wild type mice were transplanted into recipient testis of HSL-/- mice. Producing normal sperm in the seminiferous tubule of recipient mice after transplantation prove that the absence of HSL has no effect on the Sertoli cells. If there are no sperm produced in suminiferous tubule, it proves that the lack of HSL have effect on the Sertoli cells. 2. Transplant the SSC of HSL-/- mice into the testis of wild type mice. Producing normal sperm in the seminiferous tubule of recipient mice after transplantation...