Training counteracts DEX-induced microvascular rarefaction by improving the balance between apoptotic and angiogenic proteins.

This work investigated the mechanisms induced by exercise training that may contribute to attenuate dexamethasone (DEX)-induced microvascular rarefaction and hypertension. Wistar rats underwent training protocol or were kept sedentary for 8 weeks. Dexamethasone was administered during the following 14-days and hemodynamic parameters were recorded at the end. Capillary density (CD) and capillary-to-fiber ratio (C:F ratio) were obtained in soleus muscle (SOL). Also, vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2), endothelial nitric oxide synthase (eNOS), B-cell lymphoma 2 (Bcl-2), Bcl-2-like protein 4 (Bax), p-BAX and caspase-3 cleaved protein levels were analyzed. DEX treatment significantly increased blood pressure (+14%), which was associated with reduced C:F ratio (-41.0%) and CD (-43.1%). Reduction of vessel density was associated with decreased VEGF (-15.6%), VEGFR-2 (-14.6%), Bcl-2 (-18.4%), Bcl-2/Bax ratio (-29.0%) and p-Bax/Bax (-25.4%), and also with increased caspase-3 cleaved protein level (25%). Training, on the other hand, prevented microvessels loss by mitigating all proteins changes induced by DEX. In addition, angiogenic and apoptotic proteins were significantly correlated with CD, which, in turn, was associated with blood pressure. Therefore, we may point out that exercise training is a good strategy to attenuate DEX-induced microvascular rarefaction in soleus muscle and this response involves a better balance between apoptotic and angiogenic proteins, which may contribute for the attenuation of hypertension.

Effect of ß-hydroxy-ß-methylbutyrate in masticatory muscles of rats.

The aim of this research was to examine the influence of ß-hydroxy-ß-methylbutyrate (HMB) on changes in the profile of muscle fibers, whether these alterations were similar between the elevator and depressor muscles of the jaw, and whether the effects would be similar in male and female animals. Fifty-eight rats aged 60 days (29 animals of each gender) were divided into four groups: the initial control group (ICG) was sacrificed at the beginning of the experiment; the placebo control group (PCG) received saline and was fed ad libitum; the experimental group (EG) received 0.3 g kg(-1) of HMB daily for 4 weeks by gavage as well as the same amount of food consumed by the PCG in the previous day; and the experimental ad libitum group (EAG) received the same dose of the supplement along with food ad libitum. Samples included the digastric and masseter muscles for the histoenzymological analysis. Data were subjected to statistical analysis with a significance level of P < 0.05. Use of HMB caused a decrease in the percentage of fast twitch glycolytic (FG) fibers and an increase in fast twitch oxidative glycolytic (FOG) fibers in males in both experimental groups (EG and EAG). However, it produced no increase in the muscle fiber area, in either gender, in the masseter muscle. In the digastric muscle, the HMB did not change the frequency or the area of any muscle fiber types in either gender. Our data suggest that the use of HMB caused small changes in the enzymological profile of fibers of the mastication muscles; the changes were different in the elevator and depressor muscles of the jaw and the results were different depending on gender.

Effect of low-intensity pulsed ultrasound on bone regeneration: biochemical and radiologic analyses.

OBJECTIVES: The purpose of this study was to evaluate the effects of low-intensity pulsed ultrasound at 1.0 MHz on the healing process of fractures with bone loss in the rat fibula by alkaline phosphate level measurement and radiologic analyses. METHODS: Thirty 70-day-old male Wistar rats underwent a bone resection of 2.5 to 3.0 mm between the proximal and middle third of the right fibular diaphysis. The animals were randomly divided into 3 experimental groups: reference (uninjured), control (injured only), and treated (injured and treated with 5 applications of ultrasound, interspersed by 2 days of rest, beginning 24 hours after the osteotomy). Euthanasia was performed at experimental periods of 7 and 14 days. The right hind limb was removed for radiologic analysis. The blood was collected via cardiac puncture to determine the serum alkaline phosphatase activity. RESULTS: The bone fractures had not been completely consolidated in the treated and control group when analysis of the bone took place. At day 7, the serum alkaline phosphatase activity was higher in the treated group (mean ± SD, 72.17 ± 7.02 U/L) compared to the control (65.26 ± 8.41 U/L) and reference (67.21 ± 7.86 U/L) groups. At day 14, higher alkaline phosphatase activity was seen in the control group (68.96 ± 8.12 U/L) compared to the treated (66.09 ± 8.46 U/L) and reference (67.14 ± 7.96 U/L) groups. CONCLUSIONS: The biochemical and radiologic results suggest that low-intensity pulsed ultrasound can be used as an auxiliary method to consolidate fractures and probably reduces the bone healing time, offering clinical benefits.

Avaliação histológica dos efeitos do álcool no reparo ósseo da tíbia de ratos / Histological evaluation of the alcohol effcts en the rats tibia bony repair

Foram utilizados 30 animais(Rattus norvegicus) com o objetivo de avaliar histologicamente a neoformação óssea com a utilização de um modelo de alcoolismo crônico experimental em tíbia de ratos. Os animais forma separados em 2 grupos: Controle e Experimental. Os animais do Grupo Controle bebiam apenas água de dieta líquida e os do Grupo Experimental bebiam álcool etílico diluído a 6 por cento. Após 60 dias de tratamento, os animais dos dois grupos foram submetidos à cirurgia experimental na qual a tíbia recebeu uma perfuração de dois milímetros de diâmetro. Os animais foram sacrificados com 10, 20 e 40 dias após a cirurgia. Nas lâminas pode-se observar que nos três períodos a neoformação óssea foi menor em todos os espécimes do Grupo Experimental, quando comparados aos Controles. Ocorreu um retardo no preenchimento ósseo da loja cirúrgica, incompleto até os 40 dias de reparação, nos animais do Grupo Experimental. No Grupo Controle a cavidade cirúrgica estava completamente preenchida de tecido ósseo neoformado. Esses resultados permitem concluir que a dieta alcoólica interfere na reparação óssea, retardando a neoformação...