Living High-Training Low on Mice Bone Parameters Analyzed through Complex Network Approach

Abstract

The aim of this study was to investigate the effect of 8 weeks of hypoxic exposition and physical training on healthy mice femur outcomes analyzed through conventional statistic and complex networks. The mice were divided into four groups, subjected to physical training (T; 40 min per day at 80% of critical velocity intensity) or not (N), exposed to hypoxic environment (“Living High-Training Low” model – LHTL; 18 h per day, FIO2=19.5%; Hyp) or not (Nor). The complex network analysis performed interactions among parameters using values of critical “r” of 0.5 by Pearson correlations to edges construction, with Fruchterman-Reingold layout adopted for graph visualization. Pondered Degree, Betweenness, and Eigenvector metrics were chosen as centrality metrics. Two-way ANOVA, t-test and Pearson correlation were used with P<0.05. Femur phosphorus of T-Hyp was higher than all other groups (P<0.05) and correlated with bone density (r=0.65; P=0.042), bone mineral density (r=0.67; P=0.034) and% of mineral material (r=0.66, P=0.038). Overall, the complex network demonstrated improvements in bone volume, % of mineral material, bone density, and bone mineral density for T-Hyp over other groups. Association of physical training and hypoxia improved bone quality for healthy mice.