Knee-ligament loading properties as influenced by gravity: I. Junction with bone of 3-G rodents

After chronic 3-G centrifugation of rats, their bone-to-ligament junctions exhibited 95 +/- 12% of the control junctions' force-sustaining capacity (F). F was actually 29 +/- 5% greater for centrifuged rats than for control rats of comparable size, as experimental animals grew to smaller body mass. This suggests that gravity determines part of F's magnitude. These junctions are, therefore, hypothesized to be weaker after development in a weightless environment. The effect was less measurable for mice. F was measured in situ as load needed to separate the knee's medial collateral ligament from the tibia of 34 male rats (Sprague-Dawley, 27-320 d of age, exposed 4-65 d), 30 control rats, 22 male mice (Swiss Webster, 35-166 d, exposed 9-56 d), and 15 control mice.