BackgroundKnee osteoarthritis (kOA) is a common chronic disease that induces changes in redox status and inflammatory biomarkers, cell death, and motor impairment. Aerobic training can be a non-pharmacological alternative to prevent the progression of the disease.ObjectiveTo evaluate the effects of an 8 weeks moderate-intensity treadmill aerobic training program on redox status and inflammatory biomarkers and motor performance in kOA-like changes induced by monosodium iodoacetate (MIA) in rats.MethodsTwenty-seven rats were randomly divided into three groups: SHAM; induced kOA (OA); and induced kOA + aerobic training (OAE). Motor performance was evaluated by the number of falls on rotarod test, the total time of displacement and the number of failures on a 100 cm footbridge. Data for cytokines and histology were investigated locally, whereas plasma was used for redox status biomarkers.ResultsThe OA group, compared to the SHAM group, increased 1.13 times the total time of displacement, 6.05 times the number of failures, 2.40 times the number of falls. There was also an increase in cytokine and in thiobarbituric acid reactive substances (TBARS) (IL1β: 5.55-fold, TNF: 2.84-fold, IL10: 1.27-fold, IL6: 1.50-fold, TBARS: 1.14-fold), and a reduction of 6.83% in the total antioxidant capacity (FRAP), and of 35% in the number of chondrocytes. The aerobic training improved the motor performance in all joint function tests matching to SHAM scores. Also, it reduced inflammatory biomarkers and TBARS level at values close to those of the SHAM group, with no change in FRAP level. The number of falls was explained by IL1β and TNF (58%), and the number of failures and the total time of displacement were also explained by TNF (29 and 21%, respectively).ConclusionAll findings indicate the efficacy of moderate-intensity aerobic training to regulate inflammatory biomarkers associated with improved motor performance in induced kOA-like changes, thus preventing the loss of chondrocytes.

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Previous studies have highlighted the positive effects of Estradiol (E2) replacement therapy and physical exercise on skeletal muscle during menopause. However, the comparison effects of exercise training (ET) and estradiol replacement therapy during menopause on skeletal muscle have not been investigated to date. This study aimed to compare the effects of endurance exercise training versus E2 replacement therapy on mitochondrial density, redox status, and inflammatory biomarkers in the skeletal muscle of ovariectomized rats. Thirty female Wistar rats (12-week-old) were randomly assigned into three groups: Untrained ovariectomized rats (UN-OVX, n = 10); untrained ovariectomized rats treated with estradiol replacement therapy (E2-OVX); and, trained ovariectomized rats (TR-OVX). After ovariectomy, the E2-OVX rats were treated subcutaneously with E2 (implanted Silastic® capsule containing 360 μg of 17β-estradiol/mL) while the TR-OVX group performed an exercise training protocol (50–70% of maximal running speed on a treadmill, 60 min/day, 5 days/week for 8 weeks). After euthanasia, the soleus muscle was processed for histological and biochemical evaluations. Only exercise prevented the reduction of maximal oxygen consumption and increased mechanical efficiency (ME). While mitochondrial muscle density, total antioxidant capacity (FRAP), catalase (CAT) activity, and interleukin 10 levels were higher in TR-OVX, only OVX-E2 presented higher CAT activity and lower interleukin 6 levels. Endurance exercise training compared with E2 replacement therapy maintains the aerobic capacity improving the ME of OVX rats. In addition, only endurance exercise training raises the skeletal muscle mitochondrial content and tends to balance the redox and inflammatory status in the skeletal muscle of OVX rats.

Background Previous studies have highlighted the positive effects of estrogen replacement therapy during menopause. In addition, a growing body of evidence has also proven several beneficial effects of other therapeutic strategies, especially physical exercise, to counteract the deleterious effects of menopause on skeletal muscle. However, a comparison of the effects of exercise training versus hormone replacement therapy after menopause on muscle mitochondrial profile and redox/inflammatory status has not been investigated to date. The purpose of the study was to investigate the effects of endurance training versus estradiol therapy on mitochondrial density, redox status, and inflammatory biomarkers in the skeletal muscle of ovariectomized rats. Methods Thirty twelve weeks-old female Wistar rats were randomly assigned into three groups: Untrained ovariectomized rats (OVX-NAT); untrained ovariectomized rats with estrogen (ES) replacement (OVX-ER); and, trained ovariectomized rats (OVX-AT). After ovariectomy, The OVX-ER rats were treated with ES (subcutaneously implanted Silastic® capsule containing 360 µg of 17β-estradiol/mL) while the OVX-AT group performed a training protocol (50~70% of maximal running speed on a treadmill, 60 min/day, five days/week for eight weeks). All animals performed a maximal treadmill test before and after the training protocol. After euthanasia, the soleus muscle was processed for histological e biochemical evaluations. Results The maximal oxygen consumption (VO2max), mitochondrial muscle density, total antioxidant capacity (FRAP), catalase (CAT) activity, and interleukin 10 levels improved only in the OVX-AT group, while only the OVX-ER rats presented an increase in CAT activity and a decrease in interleukin 6 levels. Conclusions Both endurance exercise training and estradiol therapy improve redox and inflammatory balance in the skeletal muscle of ovariectomized rats; however, only exercise increases VO2max and mitochondrial muscle density.