aerobic exercise and celastrol: a promising combination for achilles tendon regeneration

Background: tendons are subjected to mechanical stress and strain during daily activities and physical exercise, which makes them susceptible to injury. objectives: this randomized trial evaluated the effects of a 4-week combination of training and celastrol on the healing of achilles tendon ruptures in rats. it assessed cytokine levels, gene expression, and histological changes. methods: rats with achilles tendon ruptures were randomly assigned to several treatment groups: sham, negative control, training, celastrol, and a combination of training and celastrol. eligibility criteria included age, weight, and the absence of pre-existing tendon injuries. the assessments included enzyme-linked immunosorbent assay (elisa) to measure cytokine levels [bfgf, igf1, cyclooxygenase 2 (cox2)], real-time polymerase chain reaction (rt-pcr) to analyze gene expression (scleraxis, periostin, mmp9, collagen i), and histological analysis using masson's trichrome staining to evaluate collagen organization. results: the training-celastrol group exhibited the highest levels of bfgf, igf1, and cox2, indicating a synergistic effect on tendon healing compared to the sham and negative control groups, with effect sizes of 0.85 (95% ci: 0.70 - 1.00). additionally, rt-pcr results showed that the training-celastrol group had the highest expression of scleraxis, periostin, mmp9, and collagen i, suggesting enhanced tendon repair and remodeling. histological analysis revealed that the training-celastrol group displayed the most organized collagen fibers, whereas the sham group showed regular organization, and the negative control group exhibited disorganized fibers. conclusions: the study concluded that combining aerobic training and celastrol significantly enhances tendon healing by improving cytokine levels, gene expression, and collagen organization. outcome measures were assessed at baseline, mid-treatment (week 2), and post-treatment (week 4) to evaluate temporal changes. these findings highlight the effectiveness of these therapeutic strategies in promoting tendon repair and maintaining structural integrity.