Quantity of cells of the irradiated mouse small intestine mucosa as an index of the protection degree of this organ by radioprotectors

The possibility of evaluating the radioprotective efficiency of different chemicals by the criterion of cell number in the samll intestine micous membrane was studied. Wild white mice males were gamma-irradiated at dose rate of 75 rad/min. The chemicals were administered intraperitoneally at conventional doses: cystamin dihydrochloride (CD) - 225 mg/kg, sodium S-ω-aminopropyl-β-aminoethylthiophosphate (APAETP) - 300 mg/kg, dimethylsulphoxide (DMS) - 1 ml/mouse, para-aminopropophenone (PAPP) - 30 mg/kg, 5-methoxytryptamine chloride (5-MOT) - 75 mg/kg. The latter was given 5 min before irradiation and the other chemicals 30 min before irradiation. Intestinal protection was estimated by the survival of animals during 6 days after the irradiation at 1000 rad (during the ''intestinal death'' period) and by the cell number 2 to 3 days after irradiation at 750 or 1000 rad. The number of cells in the small intestine mucous membrane was shown to represent the extent of damage caused by radiation, which allowed to use this criterion in evaluating the radioprotective efficiency of the compounds. According to their effect on the cell number in the radiosensitive intestine layer the compounds were divided into 2 groups: CD, APAETP, DMS (effective) and PAPP, 5-MOT (slightly effective). This corresponds to the extent of animal protection from the ''intestinal death'' by these compounds. The ''cell number'' criterion may be used in estimating the extent of intestinal protection by radioprotectors