EFFECT OF THE ADMINISTRATION OF SHARK TYPE I COLLAGEN TO OVARIECTOMIZED RATS

Collagen hydrolysate is of interest as a therapeutic agent of potential utility in the treatment of osteoarthritis and osteoporosis. In this experiment, we examined the effects of shark type I collagen on bone metabolism as food supplements. Shark type one collagen was extracted with 0.5M acetic acid from skin after the defatted skin. Female young (1 month old) and old (9 months old) wistar rats were used. Young rats were fed a diet containing 3% of casein for two weeks. At the ninth days of experiment, rats were either ovariectomized (ovx) and sham operated (sham). They were treated with oral doses of 400mg/kg shark collagen or casein, ovalbumin as positive control for two weeks. The bone mineral density (BMD) of the femur was measured by dual-energy X-ray absorptiometry. In all groups, the gain of body weight, bone length, and bone weight were not changed. In young rats (sham), the BMD was not changed. In young rats (ovx), collagen-treated rats showed the increase of BMD at epiphysis. We concluded that the BMD of spongy bone was increased by administration of shark collagen. In adult rats, the BMD did not show significant differences. But histomorphometric observations of the epiphysis showed that the volume of spongy bone had increased by collagen intake. By western blotting analysis using anti-type I collagen antibody, we used the samples from the epiphysis of the femur extracted with 4M guanidine hydrochloride. Type I collagen content was found to be high in epiphysis of the rats treated with shark type I collagen. These results suggested that the administration of shark type I collagen could improve osteoporosis.