Effect of athletic fatigue damage and the associated bone targeted remodeling in the rat ulna

Li Hao,Zhao Bin,Han Biao,Hao Bao-Hui,Zhang Xi-Zheng,Liu Ying-Jie,Li Rui-Xin

doi:10.1186/s12938-017-0384-1

Abstract

BackgroundFatigue damage of the long bones is prevalent in running athletes and military recruits due to vigorous mid- and long-term physical activity. The current study attempted to know the features of bony athletic fatigue damage and to explore the mechanism of fatigue damage repair through bone targeted remodeling process.MethodsRight ulnae of the Wistar rats were fatigue loaded on an INSTRON 5865 to construct the athletic fatigue damage model, and several time points (i.e. experimental days: 0, 7, 13 and 19) were selected to simulate physiological status, preliminary, mid-term and perennial stage during continuous high-intensive training, respectively. The multi-level responses of rat ulnae under the athletic fatigue loading, including cellular protein expression, micro damage or micro-crack and macro mechanical properties, were tested and statistically analyzed.ResultsWistar rats, subjected to the athletic fatigue loading protocol, experienced a decrease of ulna fatigue mechanical properties and an active bone resorption of the loaded ulnae in the early stage, whereafter, a hyperactive bone formation and significant improvements of ulnae fatigue mechanical properties were detected. However, a deterioration of quasi-static mechanical properties in the subsequent period implied limitations of bone remodeling to maintain the bearing capacity of bone during long-term strenuous exercise.ConclusionsIn summary, after athletic fatigue loading, bone targeted remodeling is activated and proceeds to repair fatigue damage, but only to a certain extent.

Highlights

Fatigue damage of the long bones is prevalent in running athletes and military recruits due to vigorous mid- and long-term physical activity
A large proportion of bone remodeling is stochastic, participating in biochemical regulation and balancing calcium salt, and the other 30% is targeted remodeling, which is specialized to repair damage or microcracks in bones according to their load situation and demands [4,5,6]
Long bone fatigue damage is prevalent in running athletes and military recruits due to vigorous mid- and long-term physical activity [8, 9]

Summary

Introduction

Fatigue damage of the long bones is prevalent in running athletes and military recruits due to vigorous mid- and long-term physical activity. Hao et al BioMed Eng OnLine (2017) 16:99 targeted remodeling processes among species that are based on the local strain or stress distribution [1, 7]. Long bone fatigue damage is prevalent in running athletes and military recruits due to vigorous mid- and long-term physical activity [8, 9]. It is characterized as generation, accumulation and coalescence of microcracks; the deterioration of mechanical properties; or even stress fractures [10, 11]. Frequency (f ), and number of cycles (N) are critical factors that influence bone fatigue damage [12, 13], and there seems to be a threshold of local peak strain that leads to destructive bone damage and bearing invalidation [14,15,16]

Methods

Results

Conclusion