Mechanism Study Of γ-ray Induced Changes Of Lymphocyte-plasmic Microfilament In Thymus Gland Of BALB/C Mice

Cytoskeleton is a kind of protein filament meshworks in eukaryocytes, its including microfilament, microtubule and intermediate filament. Microfilament is an important member of the cytoskeleton. It has effects on almost all aspects of cytobiology. The aspects are related to cytoplasmic actin, actin related proteins2/3complex (Arp2/3), capping protein (CP), cofilin, and profilin. These proteins act main roles in cytoskeleton remodeling and contraction regulating.T cell agent receptor (TCR) is a characteristic marker on all clusters of T cells, which makes complex with CD3to transduce cell signalings, form immunololgical synapse (IS), remodel the cytoskeleton, participate in T cell activation and so on. A certain dose of γ-ray will damage the nomal cells of organmism, and lymphocyte is more sensitive than others. TCR gene mutation frequency (TCR MF) is induced by radiation and its mutation frequency has dose-effect relationship with radiation. Then dose lymphocyte-plasmic microfilament meshwork be induced changes by radiation?To study the effects on actin regulation pathway and the mechanism of changes of lymphocyte-plasmic microfilament meshwork induced by γ-ray, immunofluorescent method was performed and observed features of the changes via laser scanning confocal fluorescence microscope. Arps were detected by western-blot and immunohistochemistry. Their mRNAs expression was detected by fluorescent quantitation PCR.This paper collected and analysed data of the changes of actin, TCR MF and the expression of9Arps. After2Gy γ-ray exposed, lymphocyte-plasmic F-actin begun disassembly at3h, and its disassembly rely on the time expending. Three hours after γ-ray exposed, F-actin begun disassembly at0.02Gy, and its disassembly rely on the dose increasing. After0.02Gy,0.1Gy and6Gy γ-ray exposed, TCR MF of CD4+and CD8+T cells of the exposed groups increased higher than that of non-exposed group, and the differences were statistically significant. Exposed of0.02Gy,0.1Gy and6Gy γ-ray, expressions of Arp2gene and Arp3gene were downward. Amount of Arp2/3complex was decreased. Assembly of nucleation was slow. At this moment, expression of cofiling gene was upward, it made F-actin depolymerization and microfilament disassembly quickly. Exposed of0.02Gy and0.1Gy γ-ray, expression of ZAP70gene was downward. Phosphorylation cascade reaction and recruiting proteins downstream of ZAP70was weak. On WASp regulation pathway, expression of Racl gene was upward while expression of WASp gene was downward. It promoted nucleation weakly. On WAVE/Scar regulation pathway, expression of Cdc42gene was downward while expression of WAVE2gene was upward. That was the same to WASp and Racl, Cdc42and WAVE2couldn’t promote procedure of Arp2/3complex nucleation. Then amount of daughter filament polymerization was decreaed. Exposed of6Gy γ-ray, expression of cofilin gene was in tendency of downward and proteins expression of Cdc42and WAVE2were donward, while the others expression of gene were upward. May be the tri-proteins regulate the microfilament assembly more directly than others.In conclusion, after0.02Gy,0.1Gy,1Gy and6Gy γ-ray exposed, the changes of lymphocyte-plasmic microfilament and expression of Arps gene were really happened in thymus gland of BALB/c mice. Further studies are necessary.