| People who exposure to nuclear explosion in wartime or nuclear accident in peacetime may cause the acute radiation sickness with a hematopoietic disorder, simultaneously, with a severe depression of immunological function, the suppression of producing antibodies and dislocation of cytokine nets. The response of immunological system to ionizing radiation is based on the cells participating in the immune reaction. These cells may show various changes from DMA damage, mutation and rearrangement of some important genes to abnormality of their function. This abnormality of immunological function may persist in such a long time, perhaps months , years, and even several decades. The patients will be under the very high sensitive situation because of persisting disorder of immunological function. It is not only to affect their life quality, but also may cause their aging and death. Therefore the depression of immune function induced by radiation and the treatment become a delicate problem for clinical doctors. The radiation may cause various changes of the expression and function of many cytokines participating in the regulation of cytokine nets, which is the bases of pathological change in immune system caused by radiation, and also is an important link to radiation injury and reconsistution of immune system. Hence, it posssesses very important significance to investigate the regulation nets of prominent cytokines and explore the pathological changes as well as the mechanism of radiation-induced immune system damage for their prevention and treatment.In recent years, it has been found that ionizing radiation could induce abundant lymphocyte apoptosis in immune system, and is a vital cause of immune system injury. In our department we have finished various experiments on pathological mechanism of spleen, lymph node and peripheral lymphocyte injuries incurred by radiation. Some excellent results and new insights have been obtained, bcl-2 gene family participates in the regalation of apoptosis in many tissues induced by various factors, they act on the upper stream of cell apoptosis pathway, which mainly focus in the level of mitochondria, and play a vital role in cell death. Bcl-2 protein family possesses many members, including the member of promoting and inhibiting apoptosis, the ratio of them can endow the cell sensitivity to death signal. Bel- XL is one of major members of inhibiting apoptosis in Bcl-2 family. Some authors indicated that bcl-XL-/- mice showed a severe phenotype than that of bcl-2-/-mice, because the bcl-2-/- mice die within several months, while the bcl- XL-/-mice die within embryonic stage of day 13.In the experiment, bcl-XL recombinant was constructed using reverse transcription virus vector, and transduced the bcl- XL gene into a normal human T lymphcyte (AHH1) through a technique of liposome introduction. At the same time, it was used as a control that a recombinant of similar strcture contains a enhancing green fluorescent protein. The transduction rate of lipofectin measured was 28.8%. 2-4 weeks after G418 resistance sifting, integrated stable AHH1-bcl- XL cell clones were obtained. Under fluorescent microscopy the exporession of fluorescent protein was observed in AHH1 cell transduced control gene, confirming that the transduction was successful. Moreover, by means of RT-PCR method, it was found that the expression of bcl- XL mRNA was higher significantly in AHH1-bcl- XL cells than in AHH1 cells Furthermore, the expression of Bcl-XL protein was also much more inAHHI-bcl-XL cells than in AHHI cells by using Western blot technique. Above mentioned results indicated that the model of AHH1-bcl- XL constructed was succeeded.After 0, 3, 6, 9, 12, 15 and 20Gy 60Co- -ray irradiation, it shows that, 1) Within the range of 0-12Gy, the apoptosis rates of AHH1-bcl- XL cells apparently lower than those of AHH1 cells 24h after radiation, moreover the survival rates of AHH1-bcl- XL cells were higher obviously than those of AHH1 cells. By a statistical analysis of SAS , it was found that the...
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