Protective effects of nocardia delipidated cell mitogen on the mucosa of the small intestine after irradiation of germ‐free piglets.

ABSTRACT The radioprotective effect of the bacterial immunomodulator Nocardia delipidated cell mitogen (NDCM) on intestinal mucosa and disaccharidase activities was studied in irradiated germ‐free piglets. Three‐week‐old germ‐free (GF) piglets were intragastrically pretreated with 1 mg NDCM per 1 kg body weight. The piglets were whole‐body irradiated with 2.5 Gray five days after the NDCM pretreatment and sacrificed eight days after irradiation. In the non‐irradiated group of GF piglets, NDCM application stimulated lactase activity and markedly increased sucrase activity. This stimulatory effect of NDCM disappeared after irradiation and the piglets exhibited a normal activity of lactase in the jejunal brush‐border membrane vesicles, while the sucrase activity decreased to the level found in irradiated controls. NDCM‐pretreated intestinal mucosa contained some infrequent lymphocytes which disappeared from the control irradiated tissue. It also exhibited less injury of the epithelium and stroma cells.