Effect Of Busulfan Treatments With Different Concentrations On The Spermatogenesis Of Adult Tree Shrews

As an emerging experimental animal, tree shrews are closer to primates on evolutionary status, physiological and biochemical characteristics than the rodents, example mouse,rats. Compared with other large primates, tree shrews has many advantages, such as its short reproductive cycle, fast growth and developmental cycle, as also as its cheap expense. These features above make the tree shrew to be a much better experimental animal than non-human primates, such as macaques, in biomedical research. Transgenic technology is an important and common means to study animal models if human disease in modern biomedicine; however the transgenic tree shrew has not been reported. The genetic manipulation of tree shrew will promote its applications in biomedical research. Many methods have been adopted to produce transgenic animals; here we focus on the transplantation of spermatogonial stem cells to produce transgenic tree shrew. Firstly, we erase the recipients’ own germ cells including spermatogonial stem cells and the differentiated germ cells. And then the stem cells from the donors will be transplanted into the seminiferous tubules of the recepients’ testis of which the spermatogenesis have been damaged. In the seminiferous tubules, the transplanted spermatogonial stem cells will proliferate differentiate and give rise to new sperm. The formation and development of male germ cells are regulated by age and hormone, and the spermatogenesis is not completed before puberty, the main cell testicular seminiferous tubules are consisted of supporting cells, spermatogonial stem cells, as well as spermatocyte. After the arrival of puberty, the seminiferous tubules began a continuous process of spermatogenesis, giving rise to lots of differentiated and mature sperms. There are several methods to eliminate the endogenous sperm of recipients when transplantation of spermatogonial stem cell. In mammals, Busulfan as a alkylating agent have been reported to erase the endogenous sperm successfully. Busulfan, also known as Maryland, is a nitrogen mustard alkylating agent called I,4-butanediol dimesylate and a methyl ester sulfonate representatives drugs. It is also wildly used in the treatment of chronic myelogenous leukemia and the transplantation of hematopoietic stem cell. But the side effect of long-term utilization of buslfan is associated with infertility in male. Busulfan can specifically kill the spermatogonial stem cells, without destroying the supporting cells, and the stability of the environment will help to restore spermatogonial stem cells, so it is widely used to produce the recipients in the transplantation of spermatogonial stem cell. In mice, busulfan has been adopted to the preparation of spermatogonial stem cell transplantal recipients successfully, and some also report that busulfan can prepare spermatogonial stem cell transplantation recipients in rats and macaques. To achieve the above goals, the dose of busulfan is different in different species, le. a dose of30mg/kg can effectively remove the source of spermatogonial stem cells in mice,15mg/kg in rats,8-12mg/kg in macaques. There have not any reports about the dose of busulfan in tree shrew to prepare the spermatogonial stem cell transplantation recipients. Based on the dose-time dependent effect of busulfan in tree shrews’ spermatogenesis,Our main goal of this paper is to explore the utilization of busulfan as the preparation of long-term male infertility and spermatogonial stem cell transplantation receptor model in tree shrew.ln this experiment, we found that the higher dose of busulfan, the shorter period to destroy sperm production required, the longer time needed to recover spermatogenesis, and some even may not recover. But there also exists significant differences among individuals, which may be related to the age of the tree shrew. In our7tested groups, the dose of35mg/kg could be optimal to prepare spermatogonial stem cell transplantal recipients in tree shrews, which cannot effectively remove endogenous spermatogenic cells, but irreverse the recovery process of spermatogenesis, and above all it will not lead to the death of the tree shrew. While other doses, such as15mg/kg to30mg/kg dose groups although cause damage to the spermatogonial stem cells, after some time the damaged spermatogonial stem cells could recover and produce new sperm.40mg/kg and45mg/kg dose groups results in high death rates due to the toxic effects of tree shrew.