Neuromuscular electrical stimulation but not photobiomodulation therapy improves cardiovascular parameters of rats with heart failure

The aim of the present study was to analyze the effect of neuromuscular electrical stimulation (NMES) and photobiomodulation (PBMT) on the cardiovascular parameters, hemodynamic function, arterial baroreflex sensitivity (BRS), and autonomic balance (ANS) of rats with heart failure (HF). Male Wistar rats (220-290 g) were organized into five groups: Sham (n = 6), Control-HF (n = 5), NMES-HF (n = 6), PBMT-HF (n = 6), and NMES + PBMT-HF (n = 6). Myocardial infarction (MI) was induced by left coronary artery ligation. Animals were subjected to an eight-week NMES and PBMT protocol. Statistical analysis included the General Linear Model (GLM) followed by a Bonferroni post-hoc test. Rats of the NMES-HF group showed a higher MI area than the Control-HF (P = 0.003), PBMT-HF (P = 0.002), and NMES + PBMT-HF (P = 0.012) groups. NMES-HF and NMES + PBMT-HF showed higher pulmonary congestion (P = 0.004 and P = 0.02) and lower systolic pressure (P = 0.019 and P = 0.002) than the Sham group. NMES + PBMT-HF showed lower mean arterial pressure (P = 0.02) than the Sham group. Control-HF showed a higher heart rate than the NMES-HF and NMES + PBMT-HF (P = 0.017 and P = 0.013) groups. There was no difference in the BRS and ANS variables between groups. In conclusion, eight-week NMES isolated or associated with PBMT protocol reduced basal heart rate, systolic and mean arterial pressure, without influence on baroreflex sensibility and autonomic control, and no effect of PBMT was seen in rats with HF.

Quantification of DNA Damage in Different Tissues in Rats with Heart Failure

Background

Chronic heart failure (CHF) is a complex syndrome which comprises structural and functional alterations in the heart in maintaining the adequate blood demand to all tissues. Few investigations sought to evaluate oxidative DNA damage in CHF.

Objective

To quantify the DNA damage using the comet assay in left ventricle (LV), lungs, diaphragm, gastrocnemius and soleus in rats with CHF.

Methods

Twelve male Wistar rats (300 to 330 g) were selected for the study: Sham (n = 6) and CHF (n = 6). The animals underwent myocardial infarction by the ligation of the left coronary artery. After six weeks, the animals were euthanized. It was performed a cell suspension of the tissues. The comet assay was performed to evaluate single and double strand breaks in DNA. Significance level (p) considered < 0.05.

Results

The CHF group showed higher values of left ventricle end-diastolic pressure (LVEDP), pulmonary congestion, cardiac hypertrophy and lower values of maximal positive and negative derivatives of LV pressure, LV systolic pressure (p < 0.05). CHF group showed higher DNA damage (% tail DNA, tail moment and Olive tail moment) compared to Sham (p < 0.001). The tissue with the highest damage was the soleus, compared to LV and gastrocnemius in CHF group (p < 0.05).

Conclusion

Our results indicates that the CHF affects all tissues, both centrally and peripherically, being more affected in skeletal muscle (soleus) and is positively correlated with LV dysfunction.

MALE ADULT RAT SPERM PARAMETERS AFTER SKELETAL MUSCLE INJURY

ABSTRACT Introduction: Skeletal muscle injuries stimulate a systemic inflammatory response which may interfere in species reproduction. Objective: To evaluate the effects caused by skeletal muscle injuries on the inflammatory response and sperm parameters of male adult rats. Methods: The sample group was composed of 30 Wistar rats distributed evenly across control and injury groups. Muscle injury was induced by bruising, caused by the release of a 200 g weight from a height of 30 cm onto the gastrocnemius muscle. Blood (CBC and damage/muscle inflammation markers), muscle (oxidative stress) and gonad (sperm parameters) samples were collected 72h after the injury. Results: The muscle injury increased monocytes, creatine kinase, C-reactive protein, reactive oxygen species (ROS) concentration and lipid peroxidation. In contrast, the injury reduced antioxidant capacity against peroxyl radicals (ACAP), membrane integrity (36%) and sperm acrosome (33%). Membrane integrity and acrosome (p<0.05) correlate directly with ACAP (ρ=0.602; ρ=0.513 respectively) and inversely with monocytes (ρ=-0.703; ρ=-0.635, respectively), creatine kinase (ρ=-0.450; ρ=-0.603), C-reactive protein (ρ=-0.511; ρ=-0.703) and parameters of oxidative stress (ROS ρ=-0.703; ρ=-0.635; lipid peroxidation ρ=-0.494; ρ=-0.559). Conclusion: The acute systemic inflammatory response arising from skeletal muscle injury interferes in the male reproductive cell organelles (membrane and acrosome). Level of Evidence V; Experimental study.

Qualidade de vida e capacidade funcional de idosos adscritos em um PSF da cidade de Cruz Alta - RS

O objetivo deste estudo foi comparar a qualidade de vida entre idosos autônomos e dependentes vinculados ao PSF de um bairro da cidade de Cruz Alta/RS e identificar a existência de associação entre a idade, o gênero e a avaliação subjetiva de saúde com a capacidade funcional. Foram avaliados 103 idosos com idade média de 70,8 anos (73% mulheres e 27% homens). Os instrumentos usados para avaliação da capacidade funcional foram o í­ndice de Barthel e a escala de Lawton e para avaliação da qualidade de vida, o WHOQOL-bref. A associação entre as variáveis foi estimada através do coeficiente de correlação de Pearson e através do teste do qui-quadrado. As diferenças eventuais entre as médias dos sujeitos foram estimadas através do teste t de Student. Na determinação da capacidade funcional, foram classificados 65 idosos como autônomos e 38 como dependentes. Não foi identificada associação entre a capacidade funcional e o gênero (p = 0,16). Porém houve associação entre a capacidade funcional e a idade (p = 0,000) e a avaliação subjetiva de saúde (p = 0,007). Na comparação das médias dos domí­nios do WHOQOL-bref entre o grupo autônomo e dependente, foi encontrada diferença significativa em todos os domí­nios e na qualidade de vida global. Ao final, os resultados indicaram que nos idosos que referiram uma pior avaliação subjetiva da condição da saúde há também maior dependência.Palavras-chave: Programa Saúde da Famí­lia, envelhecimento, saúde do idoso, idoso. 

Effects of l-arginine supplementation associated with continuous or interval aerobic training on chronic heart failure rats

OBJECTIVE

Chronic heart failure (CHF) is related with exercise intolerance and impaired nitric oxide (NO) production, which can lead to several functional capacity alterations. Considering the possible superiority of aerobic interval training compared to continuous training and the capacity of l-arginine to restore the NO pathway, the aim of the present study was to investigate whether these treatments are beneficial to exercise capacity, muscle mass preservation and hemodynamic, inflammatory and oxidative stress parameters in CHF rats.

METHODS

Thirty-eight male Wistar rats post 6weeks of myocardial infarction (MI) surgery were randomly assigned into 6 CHF groups: sedentary (SED, n=6); SED+Arg (n=7); ACT (n=8); ACT+Arg (n=5); AIT (n=7); AIT+Arg (n=5). Exercise test capacity (ETC) was performed pre and post 8weeks of intervention. Supplemented rats received Arg (1g/kg) by oral gavage (7×/week). Exercise training was performed on a rat treadmill (5×/week). Hemodynamic variables, tissue collection, congestion, inflammatory cytokines, and oxidative parameters were evaluated at the end of protocols.

RESULTS

All trained groups showed a superior exercise capacity compared to SED groups on the post-intervention test (p<0.0001). Pulmonary congestion was attenuated in AIT and AIT+Arg compared with the SED group (p<0.05). Left ventricular end-diastolic pressure (LVEDP) was lower in ACT+Arg, AIT, and AIT+Arg groups than SED group (p<0.05). Association of AIT with Arg supplementation was able to improve hemodynamic responses (left ventricular systolic pressure (LVSP), systolic blood pressure (SBP), +dP/dt_max, and -dP/dt_max (p<0.05), likewise, decrease muscular and renal lipid peroxidation and tumor necrosis factor (TNF)-α, and increase interleukin (IL)-10/TNF-α plasmatic levels (p<0.01). Groups that associated aerobic exercise with Arg supplementation (ACT+Arg and AIT+Arg) revealed higher gastrocnemius mass compared to the SED group (p<0.01).

CONCLUSIONS

Both aerobic training protocols were capable to improve aerobic capacity, and the association with Arg supplementation was important to attenuate muscle loss. Moreover, interval training associated with Arg supplementation elicits greater improvements in hemodynamic parameters, contributing to reduction in pulmonary congestion, and demonstrated particular responses in the inflammatory profile and in the antioxidant status.

Light-emitting diode therapy (LEDT) improves functional capacity in rats with heart failure

The syndrome of heart failure (HF) promotes central and peripheral dysfunctions that result in functional capacity decrease, leading to fatigue, dyspnea, and exercise intolerance. The use of light-emitting diode therapy (LEDT) has shown good results reducing fatigue and exercise intolerance, when applied on skeletal muscles before or after exercises. Thereby, the aim of this study was to compare the effects of LEDT on functional capacity, aerobic power, and hemodynamic function in HF rats. Male Wistar rats (230-260 g) were randomly allocated into three experimental groups: Sham (n = 6), Control-HF (n = 4), and LEDT-HF (n = 6). The animals were subjected to an exercise performance test (ET) with gas analysis coupled in a metabolic chamber for rats performed two times (6 and 14 weeks after myocardial infarction). On the day after the baseline aerobic capacity test, the animals were submitted during 8 weeks to the phototherapy protocol, five times/week, 60 s of irradiation, 6 J delivered per muscle group. Statistical analysis was performed by one- and two-way ANOVAs with repeated measures and Student-Newman-Keuls post hoc tests (p ≤ 0.05). Comparing the percentage difference (Δ) between baseline and the final ET, there was no significant difference for the VO2max variable considering all groups. However, Sham and LEDT-HF groups showed higher relative values than the Control-HF group, respectively, for distance covered (27.7 and 32.5 %), time of exercise test (17.7 and 20.5 %), and speed (13.6 and 12.2 %). In conclusion, LEDT was able to increase the functional capacity evaluated by distance covered, time, and speed of exercise in rats with HF.

Chronic electroacupuncture of the ST36 point improves baroreflex function and haemodynamic parameters in heart failure rats

Electroacupuncture (EA) has been used to treat many diseases, including heart failure (HF). This study aimed to evaluate the effects of chronic stimulation in the ST36 acupuncture point on haemodynamic parameters and baroreflex function in rats with HF. Cardiovascular parameters assessed were heart rate (HR), blood pressure (BP), and the reflex cardiovascular response of HR triggered by stimulation of baroreceptors in animals with HF subsequent to acute myocardial infarction (AMI). Male Wistar rats were divided into three groups: Sham Control - animals without HF and without EA; HF Control group - animals with HF and without EA; and HF EA group - animals with HF that received the EA protocol. Six weeks after surgical induction of AMI, the EA protocol (8 weeks, 5 times a week) was performed. The protocol was applied with EA at the ST36 point, frequency of 2 Hz, pulse of 0.3 ms and intensity of 1-3 mA for 30 min. Haemodynamic parameters and baroreceptor function were assessed. There was no difference between groups in the variables HR, systolic blood pressure (SBP) and diastolic blood pressure (DBP), which were evaluated with awake animals (p>0.05). There was an increase in the mean arterial pressure (MAP) in the HF EA group compared to the HF Control group (p<0.05). The maximum gain of the baroreflex heart rate response (Gain) was higher in the HF EA group than the HF Control and Sham Control groups. Chronic EA in the ST36 point increased the MAP and baroreflex sensitivity in rats with HF.

Ultrasound modulates skeletal muscle cytokine levels in rats with heart failure

Heart failure is a multisystemic disorder that leads to an imbalance between pro- and anti-inflammatory cytokines. Therapeutic ultrasound (TU) has been reported to modulate the inflammatory process. The aim of this study was to evaluate the effect of TU on pro- and anti-inflammatory cytokine levels in soleus muscle and plasma of rats with heart failure. Thirty male Wistar rats (230-260 g) were submitted to ligation of the left coronary artery or sham surgery. Six weeks after surgery, TU was administered directly to the right lower limb. The results indicate that TU promotes reduction of pro-inflammatory cytokine levels (tumor necrosis factor α, interleukin-6) and increases anti-inflammatory cytokine levels (interleukin-10) in the soleus muscle of rats with heart failure. This is the first study to find that TU can modulate cytokine levels in rats with heart failure. Additionally, this is a first report that TU can modulate interleukin-10 levels in the soleus muscle.

Estudo da mortalidade em população idosa de municipios do Rio Grande do Sul no período de 1996 a 2004

Estima-se que, no Brasil, a população com 60 anos ou mais será em torno de 34 milhões em 2025. O idoso vivencia em seu processo de envelhecimento uma série de alterações, que proporcionam o aparecimento de uma série de doenças que podem conduzi-lo ao óbito. Diante de tal realidade, o objetivo deste estudo foi analisar a evolução na taxa de mortalidade em idosos de municípios do interior do estado do Rio Grande do Sul, no período de 1996 a 2004, levando em consideração as faixas etárias e as diferenças entre os gêneros neste período, além de identificar as principais causas de óbitos. Dos resultados encontrados, podemos salientar que as doenças do aparelho circulatório apresentaram as taxas mais elevadas, seguidas pelas doenças do aparelho respiratório e neoplasias. Entre os gêneros, o diabetes mellitus apresenta maior prevalência entre as mulheres. Com relação à idade, as maiores taxas se encontram na população com mais de 80 anos.