Abstract: Objective To study the expression and the meaning of the vascular endothelial growth factor(VEGF) mRNA in the lung, thymus, intestines and spleen after suffering from radiative injury.Methods The mice were radiated with different doses of X ray (0,4,8 Gy) and the expression of VEGF mRNA in the lung, thymus, intestines and the spleen after 24 hours’ radiation were detected by PT-PCR. Results The expressions of VEGF mRNA in intestines and lung were found to be no significantly difference (P＞0.05) with those in normol control groups after radiated by 4 and 8 Gy ray. The expression of VEGF mRNA in the spleen and thymus gland were higher than those in normol control groups. The expressions of VEGF mRNA in the groups which radiated by 4 Gy were significantly higher than others (P＜0.01). Conclusions The expression level of VEGF mRNA become higher after different radiation dose in the spleen and thymus gland，but have no significant difference in the intestine and lung. Thus VEGF may has stronger radiative protection on immune system than in other organizations, which provides a theoratical basis for treatment of radiative injury.

Key words: VEGF, Radiative injury, Lung, Thymus gland, Intestine, Spleen, VEGF mRNA