Role of resistance training in bone macro and micro damages in an estrogen absence animal model.

AIMS: We evaluated the effects of resistance training (RT) on bone properties, morphology, and bone extracellular matrix (ECM) remodeling markers in an ovariectomy (OVX) rat model. MAIN METHODS: Thirty-six female rats were divided into four groups: sham sedentary, OVX sedentary, sham RT, and OVX RT. Rats performed RT for ten weeks, during which they climbed a ladder with progressive loads attached to the tail. Tibias were stored for dual-energy X-ray densitometry (DXA), micro-computed tomography (micro-CT), and biomechanical, biophysical, and biochemical analysis. Femurs were stored for morphological, gene expression, and gelatin zymography analysis. KEY FINDINGS: OVX decreased bone mineral density, stiffness, maximal load, and calcium content, which was reversed by RT. The trabecular number, connectivity, and MMP-13 gene expression decreased in OVX groups. Furthermore, OVX increased run-related transcription factor-2 (RUNX-2) and osteoprotegerin (OPG) gene expression, and increased the number of adipocytes in bone marrow and MMP-2 activity. SIGNIFICANCE: RT was efficient in preventing or reversing changes in bone biomechanical properties in OVX groups, improving fracture load and resilience, which is relevant to prevent fractures. On the other hand, RT did not decrease the number of bone adipocytes in the OVX-RT group. However, RT was efficient for increasing trabecular thickness and cortical bone volume, which improved bone resistance. Our findings provide further insights into the mechanisms involved in the role of RT in OVX damage protection.

Can low-level laser therapy when associated to exercise decrease adipocyte area?

Obesity affects approximately 20% of the world population, and exercise is the primary non-pharmacological therapy. The combined use of exercise and low-level laser therapy (LLLT) may potentiate the effects promoted by exercise. The objective of this study was to investigate the effects of exercise in combination with phototherapy on adipocyte area, activity of the enzyme citrate synthase and muscle morphological analysis. We used 64 Wistar rats, which were divided into eight groups with 8 rats each: sedentary chow-diet (SC); sedentary chow-diet plus laser therapy (SCL), exercised chow-diet (EC); exercised chow-diet plus laser therapy (ECL); sedentary high-fat diet (SH); sedentary high-fat diet plus laser therapy (SHL); exercised high-fat diet (EH); exercised high-fat diet, laser therapy (EHL). The animals were submitted to a program of swimming training for 90min/5 times per week for 8weeks and LLLT (GA-Al-AS, 830nm) at a dose of 4.7J/point and a total energy of 9.4J/animal, with duration of 47s, which was applied to both gastrocnemius muscles after exercise. We conclude that the combined use of exercise and phototherapy increases the activity of the enzyme citrate synthase and decreases the white adipocyte area epididymal, retroperitoneal and visceral in obese rats, enhancing the effects of exercise.

Chronic exercise partially restores the transmural heterogeneity of action potential duration in left ventricular myocytes of spontaneous hypertensive rats.

Hypertension leads to electrophysiological changes in the heart. Chronic exercise induced by a treadmill-running programme (TRP) is considered a potential non-pharmacological treatment for hypertension and may have implications in heart remodelling. However, it is not known whether the TRP is able to improve the electrophysiological properties of the heart in spontaneously hypertensive rats (SHR). In the present study, we investigated whether TRP affects the electrical properties of left ventricular (LV) myocytes isolated from different layers of the LV wall of SHR. Male SHR were divided into exercised (chronic treadmill running for 8 weeks; CEX-SHR) and sedentary (SED-SHR) groups. Age-matched normotensive Wistar male rats served as controls. Action potentials (AP) and transient outward potassium current (I(to) ) were recorded in subepicardial (EPI) and subendocardial (ENDO) LV myocytes. In normotensive controls, AP duration (APD) was longer in ENDO cells than in EPI cells. This sort of transmural heterogeneity in the LV was not observed in sedentary SHR and was partially restored in SHR subject to chronic exercise. This partial recovery was associated with an increase in I(to) density in EPI cells but not in ENDO cells. The electrophysiological changes observed in the CEX-SHR group were not accompanied by either amelioration of systolic blood pressure or a reduction in heart hypertrophy. These findings imply that a TRP is able to improve the electrophysiological parameters of isolated cardiac myocytes in SHR. This sort of adaptation contributes to the overall improvement of heart physiology in this model.

The anticancer activity of dichloromethane crude extract obtained from Calea pinnatifida.

The genus Calea is reported for many biological activities such as antiinflammatory, antiplasmodial, antifungal, antimicrobial, and cytotoxic activities. Most of the pharmacological activities are credited to germacranolides, a sesquiterpene lactone common to this genus. Dried aerial parts of Calea pinnatifida Banks were extracted with dichloromethane, which generated the dichloromethane crude extract (DCE). The main purpose of this study was to evaluate the anticancer activity of DCE performed in sulforhodamine B cytotoxicity in vitro assay against human cancer cell lines and in vivo Ehrlich models. The DCE showed a high potency and selectivity for the melanoma and kidney cell line. Two in vivo assays were also conducted in the Ehrlich ascites tumor and Ehrlich solid tumor. In the Ehrlich ascites tumor assay, the treatment with DCE increased survival rates at the highest dose (200 mg/kg). Interestingly, in the Ehrlich solid tumor, by increasing the number of treatments from one to three times a week, the tumor growth was inhibited by a lower dose (100 mg/kg). These results encouraged follow-up studies with C. pinnatifida in order to identify the active principles and to determine the anticancer mechanism of action.