Effects of Simulated Increases in Body Weight from Birth on the Growth of Limb Bones in Rats

Abstract

The purpose of this study was to subject groups of newborn male and female Sprague-Dawley rats each to a specific 10% simulated increase in body weight, to a maximum of a doubling of body weight, to study the effects of quantified, increased, intermittent, compressive forces on limb bone growth. Chronic centrifugation was employed. After 90 days of centrifugation the rats were sacrificed. The humerus, radius, ulna, femur, and tibia were removed from each animal, cleared of all soft tissues, measured and weighed. Tukey’s Studentized multiple range test was performed to identify aggregations (sets) of force groups between which there are significant differences. The data suggest that newborn male and female rats subjected to simulated increases in body weight, within the range used for this study, undergo enhanced general body growth and limb bone growth.

The Effects of Simulated Increases in Body Weight on the Developing Rat Tibia: A Histologic Study

“…When these results are compared with our findings in recent studies on the effects of simulated increases in body weight on the length of limb bones [Simon et al, 1984[Simon et al, . 1985b, definite parallels are revealed.…”

“…The results from the second of our two aforemen tioned studies [Simon et al, 1985b] have demonstrated that if rats are subjected to low levels of simulated in creases in body weight from birth, the adolescent growth period is not disturbed detrimentally. In fact, the data suggested that low levels of simulated increases in body weight (especially at 1.1 and 1.2 g) from birth enhanced the growth of limb bones; the controls had the shortest limb bones of any group.…”

“…Each group was subjected to a specific 10% simulated in crease in body weight (one group at 1.1 g, a second group at 1.2 g, etc.). When normal, male, weanling rats were used, the data revealed that the value of g and the duration of centrifugation are both significant factors in the positive effect of simulated increases in body weight on the length of limb bones [Simon et al, 1984], When newborn rats were used, the data revealed enhanced growth of limb bones among all experimental groups, when compared to the controls [Simon et al, 1985b], Using the proximal tibial epiphysial growth plate, the purpose of the present study was to compare the his tomorphology of the epiphysial growth plate among the experimental groups of both weanling and newborn rats to determine whether differences are evident that paral lel those reported for bone length in the recent studies in our laboratory. …”

The effects of simulated increases in body weight from birth on bone robusticity of limb bones of rats

“…In our earlier study investigating the effects of simulated increases in body weight from birth on limb bone length, the results revealed that both general body growth and limb bone length were enhanced (Simon et al, 1984~). The pattern suggested by the results of these two studies is one in which both limb bone length and bone robusticity are positively related with simulated increases in body weight, within the range used for these two studies.…”

Effect of Extra-Weight Loading and Aerobic Running Training on Contractile Properties of Gastrocnemius Muscle in Hamsters

“…During the last two decades, numerous studies were carried out to investigate the effect of hypergravitation on living organisms as a direct contrast to hypogravitation (i.e., zero gravity) loading which occurs in space [1][2][3][4][5][6][7][8]. Most of these studies have dealt with the effect of hypergravitation on bones, body mass and body composition.…”