Hormonal Effects on Periosteal Microvessels: A Microvascular Cast Study.

摘要

Plastic microvascular casts have been used primarily to study the three-dimensional distribution of small blood vessels in soft tissues, but in the two studies reported in bone, one investigated the vascular distribution of rat vertebrae and the other the micro-vascular distribution to both teeth and bone in the dog mandible. To this point the technique has not been used widely under experimental conditions. In this study we used the distribution of microvessels within the periosteum covering the rat parietal bones to investigate the effects of high doses of dexamethasone and prostaglandin E1 and low doses of parathyroid hormone on the microvessels of bone. Dexamethasone has been reported to decrease bone formation while the other two hormones have been reported to do just the opposite. The results showed that either prostaglandin E1 or parathyroid hormones, when given at 100 ng/rat twice a day, stimulate an increase in the number of microvessels on the surface of bone. Neither parathyroid hormones injected at 100 ng/day nor dexamethasone had any significant affect on microvessel number or size although a slight decrease in the number of microvessels appeared to occur at the highest dose of dexamethasone given (results not shown). In conclusion, we have demonstrated that capillaries found within the periosteum are very sensitive to two known stimulators of bone formation and should receive greater consideration when planning strategies to increase bone formation during bone growth and repair. (KT)