Abstract:

To investigate the effect of ionizing radiation on the expression levels of hyaluronic acid(HA) protein and hyaluronidase(HAase1) mRNA in human fibroblasts and to discuss the role of HA protein and HAase1 mRNA in the pathogenic mechanism of radiation-induced brachial plexus injury.Methods The human fibroblasts were divided into   0.5,1.0,2.0,4.0 and 6.0 Gy X-rays radiation groups and sham irradiation group (0 Gy). The morphological changes of the fiber cells after irradiated by different doses of X-rays were observed.The expression levels of HA protein and  HAase1 mRNA at 24  and 48 h after irradiated by different doses of 0,0.5,1.0,2.0,4.0 and 6.0 Gy X-rays were detected by ELISA and RT-PCR methods.Results The cells appeared vacuolization，and the nuclear chromatic began to get together after 2.0 Gy exposure;the nuclear saged and  the chromatin fractured after 4.0 Gy exposure;the nuclear saged,chromatin fractured and the part of cell plasma was dissolved after 6.0 Gy exposure.Compared with 0 Gy group,the expressions of HA protein were  increased significantly at 24 h after X-rays irradiation with the doses of 0.5,1.0,2.0,4.0 and 6.0 Gy(P<0.05) and the expression of HA protein had no  significant change  at 48 h after irradiation,but the expressions of HA protein in 4.0 and 6.0 Gy groups were increased significantly  compared with 0 Gy group (P<0.05). The levels of HAase1 mRNA were markedly increased at 24 h  after irradiated by different doses of X-rays (P<0.05).Compared with 0 Gy group,the expressions of HAase1 mRNA were increased significantly at 48 h after 1.0，4.0 and 6.0 Gy exposure compared with 0 Gy group(P<0.05).Conclusion The X-rays irradiation can induce  the increase of the expression of HA protein and the level of HAase1 mRNA in human fibroblasts ,and it may influence the occurrence and development of radiation-induced brachial plexus injury.

Key words: radiation,ionizing;fibroblasts;hyaluronic acid；hyaluronidase