bFGF基因在中子辐射肠道损伤和修复中的表达和意义

The change and significance of bFGF gene expression in the intestine of mice induced by neutron radiation

目的研究肠道经中子照后的病变特点、bFGF蛋白和mRNA的表达及意义。方法采用2.5～5.5Gy中子照射230只BALBC小鼠,于照后6和12h、1～5d、7、10、14、21和28d分批活杀,采用免疫组化和原位杂交等技术研究bFGF基因在肠组织中的表达。结果照射后隐窝细胞见凋亡与坏死,并呈剂量相关性,2.5Gy组肠黏膜见明显损伤及恢复现象。bFGF蛋白和mRNA于正常肠上皮细胞阳性,其mRNA于血管内皮和间质细胞强阳性。2.5Gy照后3d内,bFGF蛋白进行性减少,照后5～10d,绒毛上皮细胞bFGF蛋白明显增加,5d达高峰,14d恢复至正常水平。4.0Gy以上照后4d内,bFGF进行性减少。bFGFmRNA与其蛋白出现相似的变化规律,其高峰见于照后3d,10d基本恢复至正常水平。结论一定剂量的中子辐射可使肠黏膜明显损伤,并呈剂量相关性;中子照射后肠内源性bFGF基因表达参与其损伤及修复的病理过程,可能对其损伤后的修复起促进作用。

Objective To study the change and significance of basic fibroblast growth factor （bFGF） gene expression in the intestine of mice induced by neutron radiation. Methods Altogether 230 male BALB/C mice were irradiated with neutron and sacrificed at 6 hours, 12 hours, 1, 2, 3, 4, 5, 7, 10, 14, 21 and 28 days respectively after irradiation. The protein and mRNA of bFGF were detected by means of immunohistochemistry and in situ hybridization. Results Neutron radiation caused apoptosis and necrosis of cryptal cells and these changes were related to the radiation dose. The intestinal mucosa was injured and then recovered obviously in 2.5 Gy neutron group, while after over 4.0 Gy irradiation no recovery was noted. The protein and mRNA of bFGF were positive in the plasma of epithelial cells and the mRNA was also strongly positive in the endothelial and intestitial cells in normal intestinal mucosa. The bFGF protein was decreased progressively within 3 days after 2.5 Gy neutron irradiation, then increased and peaked on day 5. Recovery to normal level was seen on day 14. The bFGF protein was progressively decreased within 4 days after neutron irradiation over 4.0 Gy. The mRNA of bFGF had the similar changes to its protein, except the peak of the mRNA was on day 3 and recovery on day 10. Conclusion Some doses of neutron radiation may induce intestinal injury which has relationship with the radiation dose. The expression of endogenous bFGF gene plays an important role in the course of damage and recovery of the intestine, and may accelerate its recovery.