| Background:With the advanced technologies, people who suffer from tumors will get a better treatment and prolong their life, especially some young women, they have a necessity to recover their ability to give a birth to child. In addition, some women propose to delay pregnancy until late in life for social and financial pressures. However, they may have a risk that the success rate may be low even with help of ART. So, fertility preservation is a logical and intriguing consequence of these developments. One of the effective methods is the ovarian tissue cryopreservation. This new technology can preserve more than90%of the normal follicles, especially primordial follicles. Ovarian tissue xenotransplantation is a way to make the follicle grow, but it often faces the ischemic injury leading to follicle disappearance at the early time of transplantation. Another challenge needs to put attention to is the immune rejection. In this study, we use rabbit as a recipient to get the human ovarian tissue transplanted. This can produce a serious problem that the tissue may be useless at any time because of immune rejection. MSCs (Mesenchymal Stem Cells) is a potential cell which have abilities of muti-differentiation and immune modulatory. This is the first time that we use MSCs as a trial in the human ovarian tissue xenograft in rabbit model. We will observe the homing of MSCs in rabbit, and explore the benefits of treatments and its possible mechanism with MSCs in the human ovarian tissue xenotransplantation in rabbit model. Objective:1. To promote the efficiency of cryopreservation in order to preserve women’s fertility in reproductive age.2. To observe the migration of MSCs in the rabbit and investigate whether it can promote repair in injured sites or relieve immune rejection.3. To compare the suitable way about MSCs injection.Method:Cryopreserved human ovarian tissues are xenotransplanted into the back muscle of twenty castrated female New Zealand rabbits for8weeks. Rabbits were randomly divided into four experimental groups:(a)Group MSC:Rabbits are accepted MSCs through vein and combined with saline hypodermic injection;(b)Group FTY:Rabbits are accepted culture medium which is used in MSCs culture and FTY720hypodermic injection;(c)Group MFIV:Rabbits are accepted MSCs through vein and FTY720hypodermic injection;(d)Group MFIM:Rabbits are accepted both hypodermic injection with MSCs and FTY720. MSCs is given only once at the first day after xenotransplantion with a density of1x106per kilogram. FTY720is a kind of immunosuppressions, which is offered as a dose of2mg per kilogram every day. The models should be pretreated with FTY720for three days in Group B, Group C and Group D. MSCs used in this study should get managed with CM-Dil, a kind of fluorescence chemicals. The homing of MSCs in the whole body is observed by CLSM. Cryopreserved tissue viability are assessed by histological analysis and electron microscope. The recipient immune rejection is tested by CD4and CD8lymphocyte and IFN-γ in the blood. Graft survival was assessed by estradiol level, ovarian tissue recovery and histological analysis.Results:1. The vitrificated cryopreservation can keep human ovarian tissue as well as normal. 2. MSCs can wander in the whole body no matter vein injection or muscle injection. After8weeks, the implanting site has the highest density of cells.3. MSCs combined FTY720can better extend the endocrine ability, relieve the immune rejection, reduce ovarian tissue stromal fibrosis and necrosis rate well.4. Compared with different injection methods, we find that vein injection has more MSCs homing to the implanting site than muscle injection, and the immune rejection is much serious in the group of muscle injection.Conclusions:1. MSCs combined FTY720has better effects on promoting tissue survival and reducing immune rejection.2. Injecting MSCs especially through vein can better improve the viability of ovarian tissues and save more ovarian function. |
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