The protective effect of fermented milk kefir on radiation-induced apoptosis in colonic crypt cells of rats.
To evaluate the effect of fermented milk kefir on X-ray-induced apoptosis in the colon of rats, we examined the apoptotic index, the mean number of apoptotic cells detected by H&E staining per crypt in the colon, in control rats and kefir-pretreated rats drinking kefir for 12 days before irradiation. Apoptotic cells were confirmed by TUNEL staining, and active caspase-3 expression was studied by immunohistochemistry. The cell position of apoptotic cells and active caspase-3 positive cells were examined. The apoptotic index of kefir-treated rats was significantly (p < 0.05) decreased 2 h after 1 Gy irradiation in comparison with control rats at crypt cell positions 1-3, 5-7, 13, and 15. Active caspase-3 expression in the kefir-treated rats was also significantly (p < 0.05) reduced in comparison with control rats 2 h after 1 Gy irradiation at crypt cell positions 1-4, 13, and 15. This study indicated that kefir protects colonic crypt cells against radiation-induced apoptosis, which was most pronounced in the stem cell region of the crypt. The antiapoptotic effect of fermented milk kefir was due to the inhibition of caspase-3 activation.
D000818:Animals; D017209:Apoptosis; D003106:Colon / Q000473:pathology / Q000503:physiopathology* / Q000528:radiation effects*; D008297:Male; D008871:Microvilli / Q000473:pathology / Q000528:radiation effects; D008892:Milk; D011832:Radiation Injuries / Q000473:pathology / Q000503:physiopathology*; D011835:Radiation Protection; D051381:Rats; D017208:Rats, Wistar