Response of Bone Collagen and Connexin-43 to an Aquatic Training Program

Abstract

Exercise can increase bone mass by maintaining adequate balance between bone formation and resorption. Bone cells coordinate their responses to mechanical load by communicating via gap junctions connexons. There is no previous studies have compared the acute response of bone markers to chronic response with regard to gap junction. Aim of this study was to examine the acute response of bone markers post-exercise to pre-exercise and chronic response (adaptation) to training program. Plasma C terminal of type I procollagen (CICP) (marker for bone formation), enzyme serum band 5 tartarate resistant acid phosphatase (TRAP 5b) (marker of bone resorption) and connexin 43 (gap junction response) were assayed and compared to bone response. Methods: 15 adult sedentary females participated in an aquatic training program for 4 months aged 50.21 ± 3.07 years .Their physical characteristics and bone markers were measured pre and post-exercise before and after the program. Body composition results revealed significant variation in all parameters after program compared to that obtained before program except for percent body fat (p<0.001). Bone markers results indicated no significant variations in the blood levels of TRAP b5 and connexin 43 before program compared to that obtained after program either at rest (Pre-exercise) or after exercise (post-exercise) but was significant for CICP only in pre-exercise after the program (p<0.04). Pre-exercise compared to post-exercise either before or after program were significant in the all three investigated bone parameters (p<0.01). Results: The results indicated that bone functional adaptation is continued until the skeletal design meets the loading requirements. Post-exercise results seem to be related to the timing of the measurement of bone turnover markers relative to the last exercise bout or the diurnal variation of bone resorption markers. Conclusions: It is concluded that the changes in CICP observed following the training program indicates increased bone formation with stable resorption with net bone increase in bone mass. In addition, connexin-43 increases cell-to-cell response to exercise training program leading to adaptation in all muscloskeletal system. .