| Small intestinal villus is one of the most active tissue hyperplasia inside the body, the small intestinal mucosa epithelial cells for life is constantly update itself, a process which relies on the proliferation and differentiation of stem cells in the intestinal crypt remains replace outer terminal differentiation cells to complete.When the radiation dose<8Gy, crypt cell apoptosis, radiation dose> 14Gy, the disappearance of crypt cells, hair loss occurs. Therefore, radiation injury and the degree of recovery of gastrointestinal damage and crypt cells or stem cells, regeneration are closely related.Research progress of intestinal stem cell molecular surface marks is slow, always restricts the study of small intestinal stem cell regulation and mechanism of gastrointestinal injury. Until recent years, the use of genetic mouse models and lineage tracing technique was successfully identified a variety of intestinal stem cell surface marker molecules, determine the location of the intestinal stem cells and groupmg.Currently identified intestinal stem cells can be divided into two categories, one for resting stem cells, mainly located in the bottom of the intestinal crypt base+4 position, surface markers, including Bmi1, mTert, Hopx and Lrig1, etc., and the other labeled as Lgr5 circulating stem cells. Which, lgr5 circulating stem cells sensitive to radiation, and radiation tolerance resting stem cells can replenish circulating stem cells after activation and rapid proliferation of TA cellsOur preliminary results indicate that, S1P1 receptor modulators intestinal crypt cells showed a protective effect. SI PI is a G protein-coupled receptors SIP of phospholipid molecules, mainly in the vascular endothelial cells and lymphocytes. In the maintenance of vascular permeability and integrity, has an important role in lymphocyte development and circulation. So the first part of this experiment is mainly used with small intestinal stem cell properties logo pattern of animals, such as Lgr5tm1 (cre/ERT2) mice, Bmi1tm1 (cre/ERT) mice, to research Lgr5 continuous split ISCs and Bmil marking the static ISCs characteristics of radiation injury research S1P1 receptor modulators for the readjustment of intestinal stem cell tissue reconstruction after radiation.First, we cultivate and identify LgrStml (ere/ERT2); Gt (ROSA) 26Sortml (Smo/EYFP) and Bmi1tm1 (ere/ERT); Gt (ROSA) 26Sortml (Smo/EYFP) mice were then induced by tamoxifen establishing lineage tracing system, and 5d after induction of fluorescent cells were observed to start moving from the top of the crypt to the villus.Followed by exploration of different dose established 10Gy irradiation and radiation injury of abdominal tissue reconstruction model 12Gy irradiation of the whole body, in this model, we observed that intestinal stem cells after irradiation from the disappearance of the regeneration process. Subsequent studies of the regulation of SlPl receptor modulators of intestinal stem cells and tissues at different dose reconstruction, found SlPl receptor modulators CYM5442 on high-dose local irradiation 16Gy no effective therapeutic effect in mice; after total body irradiation 15Gy 3.5d CYM5442 not effective in increasing the number of Lgr5+cells, but can effectively promote the proliferation of crypt cells. We separate the different intestinal tissue (duodenum, jejunum, ileum, colon), 10Gy and 12Gy body irradiation found SlPl receptor agonists under CYM5442 can improve various bowel crypt regeneration after irradiation 3.5d and 7d, quantity. Applications qPCR method for detecting a 15Gy irradiation stem cell-related genes (Lgr5, olfm4, mTert, Hopx, Lrigl, Bmil, Ascl2) expression was found SlPl receptor modulator CYM5442 after irradiation 6h significantly increased expression of these genes, after irradiation Id for mTert, Bmil and other +4 allele still has to improve the role of stem cells after irradiation 3,5d related genes have little impact.Small intestine mucosa in the immune inflammatory reaction induced by radiation is high sensitive organs. Small intestine after receiving radiation injury will generate a lot of cytokines. Therefore, in the second part of the experiment, we used flow cytometry techniques focus on observation of innate immune cells such as neutrophils, monocytes-macrophages and other changes at different times after irradiation, and analysis of inflammatory immune cell infiltration and radiation injury the development of the relationship, and to study the regulation of inflammatory responses SlPl receptor modulators. We isolated mouse intestinal lamina propria cells found in the body after 15Gy irradiation 24h and 48h, SlPl receptor modulators CYM5442 can significantly reduce the number of neutrophils, but has no effect on other types of cell populations. Followed by qPCR method for detecting inflammatory factors after 15Gy irradiation-related genes (interleukin-type IL-lb, IL-6, IL-10, IL-12b, chemokines Ccl2, Ccl5, Cxcll, Cxcl2, Cxc110, adhesion molecules Icaml, Vcaml) expression was found SlPl receptor modulators CYM54426h after irradiation inhibit interleukin-class and chemokines, increase the expression of adhesion molecules. Id only increased after irradiation, interleukin-class and chemokines, adhesion molecules inhibited.3.5d after irradiation is little effect on these genes.We reveal acute radiation sickness intestinal tissue stem cells and functional reconstruction mechanisms of radiation-induced intestinal inflammation research organization through SlPl receptor modulators, the incidence of new mechanisms could be better, but also put a target-based drug design for anti-offer the foundation. |
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