Effect of Moderate- and High-intensity Resistance Training on Some Serum Anabolic/Catabolic Osteokines in Old Male Wistar Rats

Bone-related osteokines play an important role in the response of bone metabolism to physical activity. The purpose of this study was to investigate effects of different intensities of resistance training on serum levels of some osteokines associated with the Wnt signaling pathway and receptor activator of nuclear factor kappa-Β ligand (RANKL) pathway in old male Wistar rats.

Twenty-four old (23 months) male Wistar rats (mean weight: 437.93±33 g) were randomly divided into three groups of moderate-intensity resistance training (n=8), high-intensity resistance training (n=8) and control (n=8). Moderate- and high-intensity resistance trainings were performed at 60% and 80% maximal voluntary carrying capacity, respectively. The level of wclerostin, osteoprotegerin (OPG) and RANKL was evaluated by enzyme linked immunosorbent assay. Data were analyzed using one-way analysis of variance and at significance level of ≤0.05.

The results showed that sclerostin (p=0.014), OPG (p=0.049) and RANKL (P=0.034) differed significantly between the study groups. The Tukey post-hoc comparison showed that sclerostin decreased significantly in the high-intensity resistance training group  compared to moderate-intensity resistance training group (P=0.048). In addition, OPG decreased significantly in the moderate-intensity resistance training group compared to the control group (P=0.033). Moreover, RANKL decreased significantly in the high-intensity resistance training group compared to the control (P=0.048).

The results showed that resistance training with appropriate repetition and intensity can have positive effects on bone formation signaling pathways.