Scaffolds of bioactive glass-ceramic (Biosilicate®) and bone healing: A biological evaluation in an experimental model of tibial bone defect in rats.

This study aimed to investigate the in vivo tissue response of the Biosilicate® scaffolds in a model of tibial bone defect. Sixty male Wistar rats were distributed into bone defect control group (CG) and Biosilicate® scaffold group (BG).  Animals were euthanized 15, 30 and 45 days post-surgery. Stereomicroscopy, scanning electron microscopy, histopathological, immunohistochemistry and biomechanical analysis were used. Scaffolds had a total porosity of 44%, macroporosity of 15% with pore diameter of 230 µm. Higher amount of newly formed bone was observed on days 30 and 45 in BG. Immunohistochemistry analysis showed that the COX-2 expression was significantly higher on days 15 and 30 in BG compared with the CG. RUNX-2 immunoexpression was significantly higher in BG on days 15 and 45. No statistically significant difference was observed in RANKL immunoexpression in all experimental groups. BMP-9 immunoexpression was significantly upregulated in the BG on day 45. Biomechanical analysis showed a decrease in the biomechanical properties of the bone callus on days 30 and 45. The implantation of the Biosilicate® scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair.

Effects of posteroanterior thoracic mobilization on heart rate variability and pain in women with fibromyalgia.

Fibromyalgia (FM) has been associated with cardiac autonomic abnormalities and pain. Heart rate variability (HRV) is reduced in FM with autonomic tone dominated by sympathetic activity. The purpose of this study was to evaluate the effects of one session of a posteroanterior glide technique on both autonomic modulation and pain in woman with FM. This was a controlled trial with immediate followup; twenty premenopausal women were allocated into 2 groups: (i) women diagnosed with FM (n = 10) and (ii) healthy women (n = 10). Both groups received one session of Maitland mobilization grade III posteroanterior central pressure glide, at 2 Hz for 60 s at each vertebral segment. Autonomic modulation was assessed by HRV and pain by a numeric pain scale before and after the intervention. For HRV analyses, heart rate and RR intervals were recorded for 10 minutes. FM subjects demonstrated reduced HRV compared to controls. Although the mobilization technique did not significantly reduce pain, it was able to improve HRV quantified by an increase in rMSSD and SD1 indices, reflecting an improved autonomic profile through increased vagal activity. In conclusion, women with FM presented with impaired cardiac autonomic modulation. One session of Maitland spine mobilization was able to acutely improve HRV.

Low-level laser therapy enhances the expression of osteogenic factors during bone repair in rats.

The aim of this study was to evaluate the effects of low-level laser therapy (LLLT) on bone formation, immunoexpression of osteogenic factors, and biomechanical properties in a tibial bone defect model in rats. Sixty male Wistar rats were distributed into bone defect control group (CG) and laser irradiated group (LG). Animals were euthanized on days 15, 30, and 45 post-injury. The histological and morphometric analysis showed that the treated animals presented no inflammatory infiltrate and a better tissue organization at 15 and 30 days postsurgery. Also, a higher amount of newly formed bone was observed at 15 days postsurgery. No statistically significant difference was observed in cyclooxygenase-2 immunoexpression among the groups at 15, 30, and 45 days in the immunohistochemical analysis. Considering RUNX-2, the immunoexpression was statistically higher in the LG compared to the CG at 45 days. BMP-9 immunoexpression was significantly higher in the LG in comparison to CG at day 30. However, there was no expressivity for this immunomarker, both in the CG and LG, at the day 45 postsurgery. No statistically significant difference was observed in the receptor activator of nuclear factor kappa-B ligand immunoexpression among the groups in all periods evaluated. No statistically significant difference among the groups was observed in the maximal load in any period of time. Our findings indicate that laser therapy improved bone healing by accelerating the development of newly formed bone and activating the osteogenic factors on tibial defects, but the biomechanical properties in LG were not improved.

Metabolic and cardiac autonomic effects of high-intensity resistance training protocol in Wistar rats.

The aim of this study was to assess the effects of metabolic and autonomic nervous control on high-intensity resistance training (HRT) as determined by pancreatic glucose sensitivity (GS), insulin sensitivity (IS), blood lactate ([La]), and heart rate variability (HRV) in rats. Thirty male, albino Wistar rats (292 ± 20 g) were divided into 3 groups: sedentary control (SC), low-resistance training (LRT), and HRT. The animals in the HRT group were submitted to a high-resistance protocol with a progressively increasing load relative to body weight until exhaustion, whereas the LRT group performed the same exercise regimen with no load progression. The program was conducted 3 times per week for 8 weeks. The [La], parameters related to the functionality of pancreatic tissue, and HRV were measured. There was a significant increase in peak [La] only in the HRT group, but there was a reduction in [La] when corrected to the maximal load in both trained groups (LRT and HRT, p < 0.05). Both trained groups exhibited an increase in IS; however, compared with SC and LRT, HRT demonstrated a significantly higher GS posttraining (p < 0.05). With respect to HRV, the low-frequency (LF) band, in milliseconds squared, reduced in both trained groups, but the high-frequency band, in milliseconds squared and nu, increased, and the LF in nu, decreased only in the HRT group (p < 0.05). The HRT protocol produced significant and beneficial metabolic and cardiac autonomic adaptations. These results provide evidence for the positive benefits of HRT in counteracting metabolic and cardiovascular dysfunction.

Efeitos do treinamento de força sobre a função pancreática e a sensibilidade tecidual à insulina em ratos / Strength training on the pancreatic function and tissue sensitivity to insulin in rats

Estudos têm demonstrado que o exercício aeróbio promove elevação na sensibilidade tecidual à insulina (SI) e na tolerância à glicose (TG), porém a análise de tais variáveis após treinamento de força (TF) tem sido pouco explorada. Assim, o objetivo deste estudo foi avaliar os efeitos do TF sobre a TG e SI em ratos. Foram estudados 20 ratos Wistar, pareados por peso e aleatoriamente distribuídos em 2 grupos: G1 ? Sham e G2 ? TF. Todos os animais foram submetidos a 3 dias de adaptação e, subsequentemente, treinados com cargas progressivas por 3 vezes por semana, durante 8 semanas numa escada de madeira. Para avaliar SI e TG foram realizadas coletas de sangue e avaliada a cinética da glicemia pelo teste de tolerância à insulina (% de decaimento da curva; B) e o teste de tolerância à glicose (área sob a curva; AC), antes da adaptação e após o 24º dia de treinamento. A análise estatística foi realizada pelo teste t de Student pareado e não-pareado, sendo o p ? 0,05. Apenas G2 mostrou significativo aumento no B após treinamento, sendo que o delta do B entre os grupos mostrou diferenças significativas (p ? 0,05), com maiores valores no G2. Em contraste, AC não apresentou alteração significativa entre os grupos nem entre os deltas (p > 0,05). O TF promoveu benefícios adaptativos na sensibilidade tecidual à insulina, sugerindo que o TF pode ser um recurso interessante durante programas de fisioterapia cardiovascular em doenças crônicas.

Experimental studies have demonstrated that aerobic exercise promotes an increase of tissue insulin sensitivity (IS) and glucose tolerance (GT), however the analysis of such variables after strength training (ST) have been little explored. So the objective of this issue was to investigate the effects of ST on GT and IS in rats submitted to strength training (ST). We studied 20 male Wistar rats, paired by weight and randomly assigned to one of two groups: G1? training without load (Sham) and G2 ? strength training (ST). All animals were submitted to 3 days of adaptation and subsequently were trained with progressive loads 3 times a week for 8 weeks, in a wooden stair of height-1,1m and inclination-80º with a rest area on the top. To measure the IS and GT were collected blood samples and evaluated glycemic kinetic by insulin tolerance tests (% of decay-B) and glucose tolerance tests (area under the curve-AC), before the adaptation and after the 24th day of training. Statistical Analysis was performed by Kolmogorov-Smirnov test and paired and unpaired Student t-tests, with p?0.05. Only G2 showed significant increase in B after training and the delta of B showed significant differences (p?0.05) with higher values in G2. In contrast, the AC did not change between groups or deltas (p>0.05). The ST promoted beneficial adaptations in the tissue sensitivity to insulin, suggest that ST can be an interesting resource during cardiovascular physiotherapy programs in chronic diseases.

Physical exercise attenuates the cardiac autonomic deficit induced by nitric oxide synthesis blockade.

BACKGROUND: The nitric oxide (NO) synthesis blockade is characterized by an increase in the cardiac sympathetic activity and the physical training promotes the decrease in the sympathetic activity. OBJECTIVE: We investigated the effect of the NO synthesis blockade on the autonomic cardiovascular control in rats submitted to aerobic exercises during a 10-week period. METHODS: Male Wistar rats were divided in four groups: control rats, treated with chow food and water ad libitum for 10 weeks (CR); control rats, treated with N G-nitro-L-arginine methyl ester (L-NAME) during the last week (CRL); rats trained during 10 weeks on an electrical treadmill (TR); rats trained for 10 weeks and treated with L-NAME during the last week (TRL). The autonomic cardiovascular control was investigated in all groups with the use of a double blockade with methylatropine and propranolol and analysis of variability. RESULTS: The CRL and TRL groups presented hypertension. The CRL group presented tachycardia and predominance of the sympathetic tonus in heat rate (HR) measurement after the pharmacological autonomic blockade. The TR group presented bradycardia and lower intrinsic HR when compared to the others. The evaluation of the HR variability showed lower absolute and normalized values in the low frequency (LF) band in the CRL group. On the other hand, the TRL presented an increase in the LF band in absolute values. The analysis of variability of the systemic arterial pressure (SAP) showed that the CRL and TRL groups presented higher values in the LF band. CONCLUSION: The previous physical exercise prevented the deficit in the autonomic cardiac control induced by the treatment with L-NAME, but did not prevent the increase in the SAP variability.

O exercício físico atenua o déficit autonômico cardíaco induzido pelo bloqueio da síntese do óxido nítrico / El ejercicio físico atenúa el déficit autonómico cardiaco inducido por el bloqueo de la síntesis de óxido nítrico / Physical exercise attenuates the cardiac autonomic deficit induced by nitric oxide synthesis blockade

FUNDAMENTO: O bloqueio da síntese do óxido nítrico (NO) é caracterizado pelo aumento da atividade simpática cardíaca, e o treinamento físico promove a redução da atividade simpática. OBJETIVO: Investigamos o efeito do bloqueio da síntese do NO sobre o controle autonômico cardiovascular em ratos submetidos ao exercício aeróbio durante dez semanas. MÉTODOS: Ratos wistar foram divididos em quatro grupos: controle tratados com ração e água ad libitum durante dez semanas (RC); controle tratados com N G-nitro-L-arginine methyl ester (L-NAME) na última semana (RCL); treinados durante dez semanas em esteira motorizada (RT); treinados por dez semanas e tratados com L-NAME na última semana (RTL). O controle autonômico cardiovascular foi investigado em todos os grupos com a utilização de duplo bloqueio com metilatropina e propranolol, e análise da variabilidade. RESULTADOS: Os grupos RCL e RTL apresentaram hipertensão. O grupo RCL apresentou taquicardia e predomínio do tônus simpático na determinação da FC após o bloqueio autonômico farmacológico. O grupo RT apresentou bradicardia e menor freqüência cardíaca (FC) intrínseca em relação aos demais. A avaliação da variabilidade da FC mostrou menores valores absolutos e normalizados na banda de baixa freqüência (BF) no grupo RCL. Por sua vez, o grupo RTL apresentou elevação na banda de BF em valores absolutos. A análise da variabilidade da PAS mostrou que os grupos RCL e RTL apresentaram maiores valores na banda de BF. CONCLUSÃO: O exercício físico prévio impediu o déficit no controle autonômico cardíaco induzido pelo tratamento com L-NAME, no entanto não impediu o aumento na variabilidade da PAS.

BACKGROUND: The nitric oxide (NO) synthesis blockade is characterized by an increase in the cardiac sympathetic activity and the physical training promotes the decrease in the sympathetic activity. OBJECTIVE: We investigated the effect of the NO synthesis blockade on the autonomic cardiovascular control in rats submitted to aerobic exercises during a 10-week period. METHODS: Male Wistar rats were divided in four groups: control rats, treated with chow food and water ad libitum for 10 weeks (CR); control rats, treated with N G-nitro-L-arginine methyl ester (L-NAME) during the last week (CRL); rats trained during 10 weeks on an electrical treadmill (TR); rats trained for 10 weeks and treated with L-NAME during the last week (TRL). The autonomic cardiovascular control was investigated in all groups with the use of a double blockade with methylatropine and propranolol and analysis of variability. RESULTS: The CRL and TRL groups presented hypertension. The CRL group presented tachycardia and predominance of the sympathetic tonus in heat rate (HR) measurement after the pharmacological autonomic blockade. The TR group presented bradycardia and lower intrinsic HR when compared to the others. The evaluation of the HR variability showed lower absolute and normalized values in the low frequency (LF) band in the CRL group. On the other hand, the TRL presented an increase in the LF band in absolute values. The analysis of variability of the systemic arterial pressure (SAP) showed that the CRL and TRL groups presented higher values in the LF band. CONCLUSION: The previous physical exercise prevented the deficit in the autonomic cardiac control induced by the treatment with L-NAME, but did not prevent the increase in the SAP variability.

FUNDAMENTO: El bloqueo de la síntesis de óxido nítrico (NO) se caracteriza por el incremento de la actividad simpática cardiaca, y el entrenamiento físico promueve la reducción de la actividad simpática. OBJETIVO: Investigamos el efecto del bloqueo de la síntesis del NO sobre el control autonómico cardiovascular en ratones sometidos al ejercicio aerobio durante diez semanas. MÉTODOS: Se dividieron ratones wistar en cuatro grupos: control tratados con ración y agua ad libitum durante diez semanas (RC); control tratados con NG-nitro-L-arginina metil éster (L-NAME) en la última semana (RCL); entrenados durante diez semanas en cinta motorizada (RT); entrenados por diez semanas y tratados con L-NAME en la última semana (RTL). Se investigó el control autonómico cardiovascular en todos los grupos con la utilización de doble bloqueo con metilatropina y propranolol, y análisis de la variabilidad. RESULTADOS: Los grupos RCL y RTL presentaron hipertensión. El grupo RCL presentó taquicardia y predominio del tono simpático en la determinación de la FC tras el bloqueo autonómico farmacológico. El grupo RT presentó bradicardia y menor frecuencia cardiaca (FC) intrínseca en relación a los demás. La evaluación de la variabilidad de la FC mostró menores valores absolutos y normalizados en la banda de baja frecuencia (BF) en el grupo RCL. El grupo RTL presentó elevación en la banda de BF en valores absolutos. El análisis de la variabilidad de la PAS mostró que los grupos RCL y RTL presentaron mayores valores en la banda de BF. CONCLUSIÓN: El ejercicio físico previo impidió el déficit en el control autonómico cardiaco inducido por el tratamiento con L-NAME, pero no impidió el aumento en la variabilidad de la PAS.