CYTOTOXICITY OF NACL, A STOMACH TUMOR PROMOTER, AND PREVENTION BY RICE EXTRACT IN STOMACH MUCOSE OF F344 RATS

Cytotoxicity of NaCl and its prevention by rice extract were studied i n the pyloric mucosa of male F344 rat stomach after oral administratio n of rice extract and 2.6 M NaCl. Effect were observed histologically by hematoxylin and eosin staining and the bromodeoxyuridine method. Re plicative DNA synthesis (RDS) was assayed by liquid scintillation coun ter with [H-3]thymidine. NaCl(2.6 M) induced destruction of the surfac e mucous cells within 1 min. RDS and S-phase cells increased significa ntly (p < 0.01) and to a maximum at 17 h, and returned to control leve ls 48 h after exposure. Administration of aqueous rice extract 3 h bef ore NaCl exposure reduced the morphological damage to the mucosa and p revented the increase in RDS dose dependently by up to 65% (p < 0.01). These results showed that NaCl induced rapid mucosal damage and cell proliferation in rat stomach mucosa and that rice extract prevented th e damage and reduced the increase in RDS.