Radioprotective Effect of 2-Mercaptopropionylglycine on the Intestinal Crypt of Swiss Albino Mice after Cobalt-60 Irradiation

Six- to eight-week-old male Swiss albino mice were exposed to 1000 R of γ radiation from a Cobalt-60 source 30 min after a single intraperitoneal injection of 20 mg/kg body wt of 2-mercaptopropionylglycine (MPG). The crypt cells were studied quantitatively at postirradiation intervals of 3, 6, 12, 24, and 72 hr and 5, 7, 14, and 28 days. Three parameters, namely, the total cell population, the number of mitoses, and the number of pycnotic nuclei and necrotic cells, were studied. The results clearly show that the drug afforded considerable protection to the intestinal crypts by causing an early recovery from mitotic inhibition followed by an early regeneration of the crypt epithelium. The recovery is accelerated and the crypt structure is restored to near normal condition by the last interval studied, whereas, in the nonprotected controls following the initial cell death and mitotic recovery, a second phase of cell death is observed at 28 days after irradiation which may be attributed to abnormal mitoses.