Abstract:

Abstract:Objective
To study the effect of ionizing radiation on the expression of hyaluronidase(HAase) in human fibroblasts and to discuss the role of HAase in the pathogenic mechanism of radiation-induced brachial plexus injury.Methods The fibroblasts were irradiated for 24 and 48 h respectively by X-ray with doses of 0.5,1.0,2.0,4.0 and 6.0 Gy,and sham irradiation group (0 Gy X-ray) was set up.The ultrastructural changes of fibroblasts were observed by transmission electron microscope,the expression changes of protein and mRNA of HAase were detected by ELISA and real-time PCR method.
Results After irradiated　for 48 h,the nuclear chromatin began to get together in 2.0 Gy group;the nucleus and chromosome fractured and the chromosome appeared empty bubble change in 4.0 Gy group;the chromatin was no longer apparent and the apoptosis change presented early in 6.0 Gy group.After irradiated for 24 and 48 h,with the increasing of　the radiation dose,the expression of HAase protein declined,there was significant difference compared with sham irradiation group(P<0.05).The expressions of HAase mRNA in 0.5 and 4.0 Gy groups were significantly higher than that in sham irradiation group(P<0.05),but the expressions of HAase mRNA in 1.0,2.0 and 6.0 Gy groups were significantly lower (P<0.05) at 24 h.The expression of HAase mRNA in 2.0 Gy,4.0 Gy and 6.0 Gy groups were significantly higher than that in sham irradiation group at 24  h(P<0.05),the expressions of HAase mRNA in 0.5 Gy and 1.0 Gy groups were significantly lower at 48 h (P<0.05).Conclusion The increase of the radiation dose could reduce the expression of HAase in human fibroblasts,and influence the occurrence of radiation-induced brachial plexus injury.

Key words: radiation, ionizing;fibroblasts;hyaluronidase;hyaluronic acid； radiation-induced brachial plexus injury