OBJECTIVETo investigate the protective effect of manganese superoxide dismutase (MnSOD) gene transfer to small intestinal epithelial cells from radiation injury.

METHODSHerpes simplex virus (HSV) vector containing both the human MnSOD and GFP genes was introduced into mouse small intestine. Expression of MnSOD by the intestinal villi was confirmed by nested RT-PCR, immunofluorescence and enzyme activity assay. Mice were then given various doses of irradiation over the abdomen. The height of intestinal villi was measured on histopathology sections by SZ-PT optical system before irradiation, 24 h and 72 h post-irradiation. All comparisons were performed by one-way analysis of variance using the SPSS statistical software to analyze the significance between groups.

RESULTSNested RT-PCR, immunofluorescence and enzyme activity assay of MnSOD demonstrated overexpression and increased activity of MnSOD in the inoculated intestine of mice. Control (sham inoculated) irradiated mice showed decreased villi height by 40.1%-59.3% on day 1 and 44.2%-65.1% on day 3 (7.5-15 Gy). Treatment of mice with HSV-MnSOD prior to radiation led to statistically significant radioprotection of the small bowel with mean villi height decreased by only 3.1%-12.4% on day 1 and 6.3%-29.1% on day 3.

CONCLUSIONThe results demonstrate that overexpression of human MnSOD via a replication defective herpes simplex viral vector is an effective method to protect the small intestine from damage caused by ionizing radiation.