[A model of osteoporosis induced by retinoic acid in male Wistar rats].

An animal model of osteoporosis induced by retinoic acid was successfully established in 3-month-old male Wistar rats. The animals were given the drug 70 mg.kg-1.d-1 for 14 d intragastrically and sacrificed on day 29. The proximal tibia and middle tibia of the rats were processed undecalcifiedly for quantitative bone histomorphometry. Compared with the control rats, the cancellous and compact bone volume of the model rats were reduced markedly. The bone tissue microstructure showed some obvious pathological changes that the trabecular number were decreased, the separation of trabecular and medulla ossium cavity became large, the thickness of trabecular and cortex of bone were decreased. The mechanism of bone loss in the model rats was that the osteoclast was activated by retinoic acid which promoted bone resorption. Other changes in the model rats were also observed such as: the body weight, and the weights of seminal vesicle and prostate were decreased, the adrenal glands and spleen showed hyperplasia and hypertrophy. No change of the blood concentration of calcium, phosphorus, alkaline phosphatase, alanine transaminase, estradiol and testosterone in the model rats was observed.