Biomedical subjects

C C Walsh

Publications and source records attributed to C C Walsh.

4 recordsLinked to original sources

PubMed1987

Effect of body weight on osteopenia in ovariectomized rats.

Bilateral ovariectomies or sham surgeries were performed in female Sprague Dawley rats that were 78 days of age and weighed an average of 210 g. Food was available ad libitum to the control rats and to a group of ovariectomized rats (obese OVX). The food consumption of a second group of ovariectomized rats (weight-matched OVX) was restricted to match their body weights to those of the control rats. All rats were sacrificed at 14 weeks postovariectomy. Radioimmunoassay of terminal serum estradiol confirmed the success of ovariectomy. The estradiol concentration in control rats was 24.9 +/- 20.2 pg/ml, whereas the hormone was undetectable (less than 10 pg/ml) in both groups of OVX rats. The final body weights of control and weight-matched OVX rats were nearly identical (approximately 260 g). In contrast, obese OVX rats weighed significantly more than both of the above groups (approximately 320 g, P less than 0.001). The proximal tibia and lumbar vertebra were processed undecalcified for quantitative bone histomorphometry. Tibial trabecular bone volume (TBV) was determined to be 17.6 +/- 4.5%, 7.9 +/- 5.3%, and 3.6 +/- 3.1% for the control, obese OVX, and weight-matched OVX groups, respectively. Tibial TBV for both OVX groups was significantly less than the control value (P less than 0.001). The difference in tibial TBV between obese OVX and weight-matched OVX rats was also statistically significant (P less than 0.02). Histologic indices of bone resorption and formation were indicative of increased bone turnover in the proximal tibia of both OVX groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Histomorphometric analysis of rat skeleton following spaceflight.

Male Sprague-Dawley rats were placed in orbit for 7 days aboard the space shuttle. Bone histomorphometry was performed in the long bones and lumbar vertebrae of flight rats and compared with data derived from ground-based control rats. Trabecular bone mass was not altered during the 1st wk of weightlessness. Strong trends were observed in flight rats for decreased periosteal bone formation in the tibial diaphysis, reduced osteoblast size in the proximal tibia, and decreased osteoblast surface and number in the lumbar vertebra. For the most part, histological indexes of bone resorption were normal in flight rats. The results indicate that 7 days of weightlessness are not of sufficient duration to induce histologically detectable loss of trabecular bone in rats. However, cortical and trabecular bone formation appear to be diminished during the 1st wk of spaceflight.

Animals↗

PubMed1986

Histologic evidence for osteopenia and increased bone turnover in ovariectomized rats.

Bone histomorphometry was performed in the proximal tibia and lumbar vertebra of female Sprague-Dawley rats subjected to either bilateral ovariectomy or sham surgery. Ovariectomized rats killed 10 weeks after surgery were characterized by osteopenia and histomorphometric indices of increased bone turnover at both skeletal sites. Osteoclast surface and number as well as osteoblast surface and number were significantly increased in ovariectomized rats. Tetracycline-based data were consistent with accelerated bone formation in response to ovariectomy. Active formation surface (double-labeled surface), calcification rate, and bone formation rate (tissue level, total surface referent) were all significantly elevated in the proximal tibia of ovariectomized rats. Ovariectomy also increased active formation surface and bone formation rate in the lumbar vertebra, but the vertebral calcification rate was nearly identical in control and ovariectomized rats. Osteopenia and dynamic tetracycline-based estimates of increased bone turnover in ovariectomized animals were more pronounced in the proximal tibia relative to the lumbar vertebra. Longitudinal bone growth in the proximal tibia and mineralization lag time at the tibial cortical endosteal surface were not affected by ovariectomy. These histomorphometric data indicate that ovariectomy induces osteopenia and accelerated skeletal metabolism in rats.

Animals↗

PubMed1985

Skeletal alterations in ovariectomized rats.

Female Sprague Dawley rats were subjected to either bilateral ovariectomy or sham surgery. Tetracycline derivatives were administered to each rat on two separate occasions to label sites of bone formation. All rats were sacrificed at 5 weeks postovariectomy and their proximal tibiae were processed undecalcified for quantitative bone histomorphometry. A twofold decrease in trabecular bone volume was noted in the proximal tibial metaphysis of ovariectomized rats. This bone loss was associated with elevated histomorphometric indices of bone resorption and formation. Ovariectomy increased osteoclast surface and numbers as well as osteoblast surface and numbers. Elevations in calcification rate and fractional trabecular bone surface with double tetracycline labels also suggest that bone formation was stimulated in ovariectomized rats. In addition, ovariectomized rats exhibited a greater rate of longitudinal bone growth relative to sham-operated control rats. These histomorphometric data indicate that ovariectomy induces marked bone loss and accelerated skeletal metabolism in rats.

Animals↗