Influence of nutritional factors on bone collagen fibrils in ovariectomized rats.

The influence of both vitamin D(3) and Ca:P ratio on bone collagen fibrils was investigated in ovariectomized rats. Six weeks after ovariectomy the rats were maintained for 80 days with diets containing vitamin D(3) and calcium supplementation. Age-matched ovariectomized animals were fed a normal diet. When vitamin D(3) was increased in the diet, although no effect in fibril organization was observed in relation to that from ovariectomized rats with the normal diet, a highly significant effect in fibril diameter was detected. When the calcium:phosphorus (Ca:P) ratio was increased from 1:1 to 2:1 (without vitamin D(3) supplementation) both structural fiber parameters were significantly affected. The results were closer to normal (i.e., collagen fibrils from animals without ovariectomy) when vitamin D(3) and Ca:P ratios were combined.