SCANNING ELECTRON MICROSCOPIC AND ENZYME HISTOCHEMICAL OBSERVATIONS ON THE CADMIUM-AFFECTED GASTRO-INTESTINAL VILLI OF MICE

Abstract

Orally administered cadmium has been known to cause diarrhea and flatulence of the gastrointestinal tract. Scanning electron micro-scopic observations revealed that the absorptive cells on the tip of the intestinal villi were affected to some extent by administration of 2.5 μg CdSO₄/10 g of body weight (b.w.). Administration of higher doses of CdSO₄ made the microvilli of the absorptive cells sparse and caused degeneration of the cells. Strong enzymic activities of alkaline phosphatase, acid phosphatase, magnesium-dependent ATPase, and sodium-potassium-dependent ATPase were recognized at the microvilli of the absorptive cells of the villi in the control mice. The enzymic activities of magnesium-dependent ATPase and sodium-potassium -dependent ATPase became weak with increasing dosages of CdSO₄. The microvilli of the absorptive cells showed a strong alkaline phosphatase activity at a dose less than 25 μg CdSO₄/10 g of b. w., while some inhibitory effects could be recognized with 50 μg/10 g of b. w. After administration of 2.5 μg CdSO₄/10 g of b. w., no acid phosphatase reaction products were found only at the absorptive cells located on the tip of the villi. Administration of a large quantity more than 5 μg/10 g of b. w. strongly affected the acid phosphatase activity. It may be possible that the digestive functions are impaired by low cadmium administration.