Massive large bowel resection decreases bone strength and magnesium content but not calcium content of the femur in rats

We examined the effects of massive large bowel resection (cecocolonectomy) on calcium and magnesium absorption and bone characteristics in rats. Male Sprague-Dawley rats were divided into two groups: sham-operated and cecocol onectomized rats. The rats were fed a sucrose-based diet containing casein at 250 g/kg diet for 10 d after a 9- to 10-d postoperative recovery period. Apparent magnesium absorption but not calcium absorption was lower in the resection group than in the sham group. There was a tendency of lower serum magnesium concentration (P = 0.070) but not calcium concentration (P = 0.4 18) in the resection group compared with the sham group. The maximum breaki ng force and magnesium content but not the calcium content of the femur wer e lower in the resection group than in the sham group. These results sugges t that massive large bowel resection influences magnesium kinetics and decr eases bone strength through reduction of the magnesium content of the femur in rats. Femoral breaking force was positively correlated (r = 0.617, P = 0.011) with only the magnesium content. We conclude that the changes in mag nesium kinetics caused by cecocolonectomy could contribute to the fragility of bone.