Spontaneous cure of rickets in rats

Abstract

It has long been believed that in infants healing of rickets occurs in spite of the diet and environment remaining unchanged. Some time ago in the course of an experiment on the curative effect of sunlight in the rickets of rats, it was observed that rickets healed in two of the control animals. One of these rats was on the Sherman and Pappenheimer diet plus 25 mg. P. per cent. and the other on the same diet with an addition of 50 mg. P. per cent. The rats weighed 34 g. at the outset, and after 30 days showed rickets by x-ray. After 62 days the radiograph was negative in one instance and demonstrated healing in the other. Autopsies of both revealed no gross rachitic changes; microscopic examination showed healed rickets at the costo-chondral junctions in one instance, in the other no rickets was found but some autolysis had taken place.

In view of this experiment another series of rats were put on the same diet (Sherman and Pappenheirner plus 25 mg. P. per cent., in the form of secondary potassium phosphate). This addition furnishes a level of phosphorus which is still inadequate for the rat, and leads to rickets. Of the four receiving this diet all showed signs of rickets according to x-ray after 32 days. After 48 days, however, the radiographs showed healing. During this period the rats had made a total gain of 92 g. After 74 days the x-ray showed the lesions apparently healed, and the rats were killed. No gross evidences of rickets were found at necropsy. Microscopic examination of the costo-chondral junctions also showed no evidences of active rickets; the rickets was either healing or there was merely osteoporosis.