Fig 1.
Bone formation at periosteal surface is affected by genotype and exercise during growth.
A) Representative image of the new tissue identified at the endosteal and periosteal surfaces, along with the pre-existing tissue in-between (bar = 500 μm). The area of tissue between florescent labels was used to quantify B) new endosteal tissue, C) pre-existing tissue, and D) new periosteal tissue. Main effects are noted for genotype (G), physical activity (A), and their interaction (GxA). Individual differences with a p<0.05 were found when compared to sedentary-PPRfl/fl (‡), and exercised-PPRfl/fl (*). Mean ± stdev (n = 10). D).
Table 1.
Mouse body weights along with the structural geometry, histomorphometry, and mechanical properties of the tibia in response to physical activity and genotype.
Mean ± stdev (n = 10).
Fig 2.
In sedentary mice the cortical area and structural-level properties of the tibia are scaled to body weight between genotypes.
Cortical cross-sectional area, ultimate load, and stiffness of sedentary mice were normalized to body weight. Student t-tests found differences between groups not significant (n.s.), suggesting that structural properties are scaled to body weight in the absence of PPR expression. Mean ± stdev (n = 10).
Table 2.
Structural-level properties of the tibia are influenced by PPR expression along the osteoblast lineage.
Mean +/- stdev (n = 10).
Table 3.
The absence of PPR expression along the osteoblast lineage reduces the impact of exercise on the tissue-level properties of the tibia.
Mean ± stdev (n = 10).