Nitric oxide and radiation enteritis.

OBJECTIVE

To investigate the changes in intestinal nitric oxide (NO) and myeloperoxidase (MPO) concentrations, the rate of endotoxaemia, and intestinal mucosal structure in rats after irradiation of the abdomen and to find out the effect of Nomega-nitroarginine methyl ester (L-NAME) inhibition NO synthesis.

SETTING

Medical school, Turkey.

DESIGN

Experimental study.

MATERIAL

46 Wistar-albino rats.

INTERVENTIONS

In Group I (n = 12), rats underwent abdominal irradiation alone. In Group II (n = 12), they underwent abdominal irradiation and were given L-NAME orally for 3 days before and 3 days after irradiation. In Group III (n = 12), rats had abdominal irradiation and were given L-NAME orally for 3 days after irradiation. Group IV (n = 10) were controls and were untreated. The irradiation procedure consisted of a single shot of 1000 cGy to the abdomen and L-NAME was given 30 mg/kg/day orally in the drinking water.

MAIN OUTCOME MEASURES

Intestinal mucosal MPO and nitrite, and plasma endotoxin concentrations. Changes in villous height and number were recorded.

RESULTS

In groups II and III, MPO and NO2- concentrations decreased significantly compared with group I. Mucosal integrity was protected in both groups treated with L-NAME (groups II and III) in contrast to the group given irradiation without treatment (group I).

CONCLUSION

These results suggest that the NO pathway contributes to the inflammatory response of radiation enteritis. Inhibition of NO synthesis may have a beneficial effect in the treatment of inflammation caused by irradiation.