Evaluation of the Diaphragm Muscle Remodeling, Inflammation, Oxidative Stress and Vascularization in Smokers: An Autopsy Study.

BACKGROUND/AIMS: Cigarette smoking is a key factor in systemic inflammation and oxidative stress, and it has also been associated with the loss of muscle strength and an elevated risk of pulmonary diseases. Thus, this study aimed to analyze the effects of cigarette smoking on the diaphragm muscle structure of postmortem samples. METHODS: Immunohistochemical techniques were used for muscle remodeling (metalloproteinases 2 and 9), inflammation (cyclooxygenase-2), oxidative stress (8-hydroxy-2'-deoxyguanosine), and vascularization (vascular endothelial growth factor). Hematoxylin and eosin stain was used for histopathological analysis and Picrosirius stain was used to highlight the collagen fibers. RESULTS: Cigarette smokers had an increase of diaphragm muscle remodeling, oxidative stress, inflammation, and vascularization compared to non-smokers. CONCLUSION: Diaphragm muscle structure may be negatively affected by cigarette smoking.

Cigarette Smoking Impairs the Diaphragm Muscle Structure of Patients without Respiratory Pathologies: An Autopsy Study.

BACKGROUND/AIMS: Smoking is a major risk factor for several cardiovascular and pulmonary diseases, and it has also been associated with the loss of skeletal muscle mass and strength leading to sarcopenia. The aim of this is study is to analyze the effects of cigarette smoking on the diaphragm muscle histopathology of postmortem samples from patients without respiratory diseases. METHODS: Diaphragm samples were stained with hematoxylin and eosin for histopathological analysis. Picrosirius stain was used to highlight the collagen fibers. RESULTS: Cigarette smokers had an increase of histopathological alterations as abnormal cytoplasm, abnormal fiber size and shape, and central nucleus. Additionally, smokers had an increase of collagen fibers on diaphragm muscle. CONCLUSION: Smoking may influence in a negatively fashion the diaphragm musculature.

Physical exercise alters hepatic morphology of low-density lipoprotein receptor knockout ovariectomized mice.

To explore the effects of physical exercise on the liver of animals in menopause, we analyzed the histomorphometric parameters of the hepatic tissue in ovariectomized and dyslipidemic female mice. The animals were distributed in six groups (n = 5): sedentary control (SC), sedentary ovariectomized control (SOC), trained ovariectomized control (TOC), sedentary LDL knockout (LDL-S), sedentary ovariectomized LDL knockout (LDL-SO), and trained ovariectomized LDL knockout (LDL-TO). At the end of the experiment, the liver and the visceral adipose tissue (VAT) of animals were removed for morphometric and stereological studies. In the LDL-S and LDL-SO animals, both sedentary, results showed reduction in the area (µm2) and major and minor diameters (µm) of hepatocytes and reduction in the portions of large hepatocytes, and increase in the percentage of Kupffer cells. The trained group showed a tendency of increase in the area and diameter and in the percentage of hepatocytes, as well significant reduction in the percentage of Kupffer cells and interstitial tissue. We suggested that training can prevent cell and tissue damage caused by the process of increase in hepatic fat, lipoperoxidation, and tissue inflammation in animals with privation of estrogen and dyslipidemia, apparently reflecting a better metabolic response of the hepatic tissue in organisms undergoing training.

Reference database of hematological parameters for growing and aging rats.

The normal hematological values in various phases of the rat life provide a valuable guide to researchers and could be useful for experimental works. However, database information available on the literature are incomplete. AIM: This study aimed to present normal hematological parameters of young and aged rats. METHODS: Male and female rats were distributed into seven experimental groups with 1, 2, 3, 6, 12, 18, and 24 months of age. Blood samples taken from the tails were analyzed. Normal hematological values were determined for each age group. RESULTS: Rats showed a progressive weight gain with advancing age, predominantly after 3 months of life. With advancing age, differences were found on hematological parameters: some of them showed a progressive rise with age and others did not. Hemoglobin levels and hematocrit did not change while the number of circulating red blood cells suffered slight increase. CONCLUSION: The present study determined the normal values for absolute and relative hematological parameters in Wistar rats from 2 to 24 months for male and female rats. The results can be used in studies of effects of aging, feeding, and medications on growing and aging rats.

Effects of resistance training on liver structure and function of aged rats.

The aging process may cause negative physiological changes. However, exercises as resistance training (RT) have been considered an important intervention to attenuate these changes. Additionally, liver plays an important role in blood glucose homeostasis in exercise. AIM: This study aimed to analyze the effects of RT on the liver components of aged animals. METHODS: Male Wistar rats were divided into two groups: 24 months' group (CONTROL); and group submitted to a progressive RT protocol for 16 weeks (EXERCISE). Both groups were sacrificed at 24 months. RESULTS: We observed a decrease in blood flow due to the practice of resistance exercises. Besides, our results showed that hepatic tissue plays an important role in glycemic homeostasis during RT. In addition, RT increased mitogen capacity of hepatocytes. CONCLUSIONS: Our study showed many implications for the knowledge about the effects of strength training on old animals' liver.

Effects of testosterone administration on liver structure and function in aging rats.

Aging males have a decrease in testosterone levels, by which the testosterone treatment may influence in a negatively fashion the liver. AIM: This study aimed to analyze the effects of aging with or without testosterone administration on the liver components of animals. METHODS: Wistar rats were divided into three groups: 20 months' group (G20), 24 months' group (G24), group treated with testosterone for 16 weeks (GT). All groups were sacrificed at 24 months except for G20 that was sacrificed at 20 months. RESULTS: Aging and testosterone treatment alters the body weight (BW), liver weight (LW) and relative liver weight. Besides, testosterone increased the mitogen capacity of hepatocytes. Nonetheless, we reinforce the negative effects of testosterone on old animals' liver as chronic hepatic congestion and/or cholestasis. In addition, we observed that testosterone plays an important role on hepatic glycogen stores. CONCLUSIONS: Our study showed many implications for the knowledge about the effects of aging with or without testosterone administration on old animals' liver.

Caloric restriction minimizes aging effects on the femoral medial condyle.

This study aimed to analyze the effects of caloric restriction on aged femoral articular cartilage of Wistar rats. Three groups of eight animals each were considered: young (YC) and old (OC) control groups fed with a normal diet and old caloric restriction group (OCR) composed of 18-month-old animals fed with a 31% less caloric diet from 6-months of age. Articular cartilage was studied through morphometry and immunohistochemistry. Body mass was 12% less in the OCR group than in the OC group. The articular cartilage from OC rats show thinner medial condyles, fewer chondrocytes, smaller chondrocytes nuclear volume and, in both condyles, a predominance of collagen type II and less collagen density compared to both YC and OCR groups (p < .001). In contrast, OCR articular cartilage show thicker medial condyles, larger chondrocytes nuclear volume and increased collagen density compared to OC group (p < 0.001). We concluded that caloric restriction minimizes the effects of aging on medial condyles of the femoral articular cartilage.

Effects of moderate exercise on the biochemical, physiological, morphological and functional parameters of the aorta in the presence of estrogen deprivation and dyslipidemia: an experimental model.

BACKGROUND: The estrogen deficiency, abnormal lipid profile, weight gain and a sedentary lifestyle are factors associated with the increased prevalence of cardiovascular disease in menopausal women. However, physical exercise practice reduces some of these risk factors. Moreover, it has been shown that exercise has an impact on inflammation, in sympathetic activity and improves endothelial function. AIMS: The present study aims to evaluate the effects of moderate aerobic training on biochemical, morphological and physiological parameters in LDL Knockout mice with estrogen deprivation, evaluating the components of the ascending aortic wall. METHODS: The animals were randomly divided into six groups (n=5): sedentary control (SC), sedentary control ovariectomized (SCO), trained control ovariectomized (TCO), LDL-Knockout sedentary (KS), LDL-Knockout sedentary ovariectomized (KOS) and LDL-Knockout trained ovariectomized (KOT). The trained groups underwent a protocol of moderate training for 4 weeks on a treadmill with speed and progressive load. After training, blood samples were collected for biochemical assessments and the aorta was removed for dissection and histological morphometry study. In addition, the expression of angiotensin-converting enzyme (ACE) and angiotensin II proteins were examined by immunohistochemistry in all groups of animals. RESULTS: Changes of expressions of ACE and angiotensin II were found when the group was subjected to exercise. The concentrations of cholesterol and triglycerides were lower in the groups of animals with estrogen deprivation and dyslipidemia. In animals that performed exercises we found significant increase (p<0.05) in Vv[lam]; decrease in Vv[col] and CWT, and a tendency for decrease both in TS and IMT when compared to the SC groups. The histological morphometry findings showed consistency in the results of the aorta study when the ovariectomized group underwent the exercise protocol. CONCLUSION: We conclude that physical training contributed to reducing vessel rigidity and to improvements in vascular compliance, with the increase in volume density of elastic lamellae in the estrogen-deprived groups who had normal cholesterol levels.

Resistance exercise and testosterone treatment alters the proportion of numerical density of capillaries of the left ventricle of aging Wistar rats.

UNLABELLED: Changes in the heart compartments that leads to pathological cardiac hypertrophy can be related to testosterone reduction in aging males since heart cells are susceptible to androgens. Resistance exercise delays the changes of aging. AIM: This study aimed to analyze alterations of the left ventricle of aged rats subjected to resistance exercise with administration of testosterone. METHODS: Wistar rats were divided into five groups: C Group (control), S Group (sedentary), ST Group (sedentary treated with testosterone), T Group (trained) and TT Group (trained and treated with testosterone), strength training protocol and testosterone treatment were 16 weeks long. All groups were sacrificed at 16 months except for C group, sacrificed at 13 months. RESULTS: There was no change in the weight of the heart or the left ventricle between the groups. ST group showed increase in Nv [cap] density of capillaries and collagen, with no differences in interstitial space. Both trained groups (T and TT) showed increase in the numerical density of capillaries (Nv [cap]) and in the interstitial space, with no changes in collagen. CONCLUSION: Resistance exercise combined with testosterone triggered a response of compensatory adjustment in the increase of Nv [cap], collagen and interstitial space, increasing perfusion and nutrition to the heart.

The effects of joint immobilization on articular cartilage of the knee in previously exercised rats.

Studies have determined the effects of joint immobilization on the articular cartilage of sedentary animals, but we are not aware of any studies reporting the effects of joint immobilization in previously trained animals. The objective of the present study was to determine whether exercise could prevent degeneration of the articular cartilage that accompanies joint immobilization. We used light microscopy to study the thickness, cell density, nuclear size, and collagen density of articular cartilage of the femoral condyle of Wistar rats subjected to aerobic physical activity on an adapted treadmill five times per week. Four groups of Wistar rats were used: a control group (C), an immobilized group (I), an exercised group (E), and an exercised and then immobilized group (EI). The right knee joints from rats in groups I and EI were immobilized at 90 °C of flexion using a plastic cast for 8 weeks. Cartilage thickness decreased significantly in group I (mean, 120.14 ± 15.6 µm, P < 0.05), but not in group EI (mean, 174 ± 2.25), and increased significantly in group E (mean, 289.49 ± 9.15) compared with group C (mean, 239.20 ± 6.25). The same results were obtained for cell density, nuclear size, and collagen density (in all cases, P < 0.05). We concluded that exercise can prevent degenerative changes in femoral articular cartilage caused by immobilization of the knee joint.

Smoking Intensity Increases Diaphragm Muscle Injury: A Clinicopathologic Study.

BACKGROUND: Studying the effects of smoking intensity is important to evaluate the risk of tobacco use on a range of illnesses, such as as sarcopenia among the elderly. Thus, this study aimed to analyze the effects of pack-years of cigarette smoking on the diaphragm muscle (DIAm) histopathology of postmortem samples. METHODS: Subjects were divided into three groups: never-smoker (n = 46); less than 30 pack-years of smoking (n = 12); and more than 30 pack-years of smoking (n = 30). Diaphragm samples were stained with Picrosirius red and hematoxylin and eosin stain for general structure. RESULTS: Participants with more than 30 pack-years of cigarette smoking had a significant increase in adipocytes, blood vessels and collagen deposit, as well as an increase in histopathological alterations. CONCLUSIONS: Pack-years of smoking was associated with DIAm injury. However, further clinicopathological studies are needed to confirm our findings.

Acute exercise adjustments of cardiovascular autonomic control in diabetic rats.

INTRODUCTION: We evaluated the role of cardiovascular autonomic changes in hemodynamics at rest and in response to exercise in streptozotocin-induced diabetic rats. METHODS: Male Wistar rats were divided into nondiabetic (ND, n = 8) and diabetic (D, n = 8) groups. Arterial pressure signals were recorded in the basal state and after atropine or propranolol injections at rest, during exercise and during recovery. RESULTS: At rest, vagal tonus was reduced in D (37 ± 3 bpm) in comparison with the ND group (61 ± 9 bpm). Heart rate during exercise was lower in D in relation to ND rats associated with reduced vagal withdrawal in the D group. The D rats had an increase in vagal tonus in the recovery period (49 ± 6 bpm). CONCLUSIONS: Exercise-induced hemodynamic adjustment impairment in diabetic rats was associated with reduced cardiac vagal control. The vagal dysfunction was attenuated after aerobic exercise, reinforcing the positive role of this approach in the management of cardiovascular risk in diabetics.

Quantification of left ventricular myocardial collagen system in children, young adults, and the elderly.

Studies on the collagen system of the human myocardium are still limited compared to those on small laboratory animals. The aim of this work was to observe the collagen tissue of the myocardium of the human heart as a function of age. The types of collagen, as well as the density of collagen tissue and the diameter of collagen fibrils, were examined. Fragments of the left ventricular wall from 15 hearts, 5 from children, 5 from young adults, and 5 from elderly individuals, were analyzed by using the Picrosirius-polarization method and by transmission electron microscopy (TEM). The results showed the presence of collagen type III and collagen type I, both in the endomysium and perimysium of the 3 groups studied. Measurements of collagen content in myocardial tissue displayed that both endomysial and perimysial collagen increase in number and thickness in the adult and elderly. These histochemical results coincided with the observations obtained with the electron microscope in showing an increase in the number of collagen fibrils with a large diameter in the adult and elderly hearts. The present results on cardiac collagen may be important for assessing the pathogenesis of several cardiopathies in the hearts of children, young adults, and the elderly.

Effects of aging on the secretory apparatus in the right atrial cardiomyocytes of rats.

The cardiac atria secrets polypeptide hormones usually called natriuretic peptides (NPs). These substances play a relevant role in the blood pressure regulation. The objective of the study was to estimate the effects of aging on the secretory apparatus of NPs in cardiomyocytes of the right atrium. Twenty male Wistar rats were studied: 10 young animals aged 3 months old (237 ±â€¯27 g; mean ±â€¯SD) and 10 old animals aged 20 months old (450 ±â€¯68 g; mean ±â€¯SD). The systolic blood pressure was verified instants before the moment of the euthanasia. Electron micrographs were prepared to quantify the area and density of the NP granules and the relative volumes of the endoplasmic reticulum, Golgi complex, and mitochondria. In addition, the number of pores per 10 µm of karyotheca was another variable evaluated. The significance of the results between the two groups evaluated was analyzed by the Student's t test (p < 0.05). The cardiomyocytes obtained from animals of the old group showed decreased in sectional area and density of secretory granules of NP and lower relative volume of endoplasmic reticulum, Golgi complex, and mitochondria compared with the young rats. Moreover, the quantitative density of nuclear pores was significantly lower compared with the youngers. CONCLUSION: Aging causes hypotrophy of the cardiomyocytes of right atrium, similar to what occurs in ventricular cardiomyocytes.

Diaphragm muscle structure in the elderly: Findings from an autopsy study.

Sarcopenia is characterized as aging-related weakness and atrophy, which decreases the diaphragm force generating capacity leading to a decrease of expulsive non-ventilatory motor behaviors, which are critical for airway clearance. Thus, this study aimed to analyze the histopathology of the diaphragm in postmortem samples. Thirty individuals were included. Diaphragm samples were stained with hematoxylin and eosin for histopathological analysis. Picrosirius stain was used to highlight the collagen fibers. We observed a positive association between advancing age and histopathological findings in the diaphragm structure. We suggest that age is a key factor in increasing diaphragm muscle histopathology. However, further clinicopathological studies are needed to confirm our findings.

Ultrastructural effects of diabetes in the right atrium cardiomyocytes of elderly Wistar rats.

The present study aimed to evaluate the effects of diabetes on quantitative parameters of right atrial cardiomyocytes of elderly rats. Wistar rats (14 months of age) were divided into two groups: streptozotocin-diabetic rats (DG) and control rats (CG). The groups were sacrificed at 16 months. Ultrafine sections of the right atrium were analyzed by electron microscopy. In elderly diabetic animals, histograms of the frequency distribution of natriuretic peptides according to their size showed increased number of small and medium peptides in relation to large peptides, which increased its numerical density leading to a decrease in the mean diameter of both natriuretic peptides. However, elderly diabetic animals remained normotensive. No significant difference was observed between the groups for the volume density of mitochondria, endoplasmic reticulum, and Golgi apparatus. In conclusion, elderly diabetic rats showed increased functional activity of atrial cardiomyocytes with greater production of natriuretic peptides in association with a quantitative maintenance of cytoplasmic components.

Low-intensity treadmill exercise-related changes in the rat stellate ganglion neurons.

Stellate ganglion (SG) represents the main sympathetic input to the heart. This study aimed at investigating physical exercise-related changes in the quantitative aspects of SG neurons in treadmill-exercised Wistar rats. By applying state-of-the-art design-based stereology, the SG volume, total number of SG neurons, mean perikaryal volume of SG neurons, and the total volume of neurons in the whole SG have been examined. Arterial pressure and heart rate were also measured at the end of the exercise period. The present study showed that a low-intensity exercise training program caused a 12% decrease in the heart rate of trained rats. In contrast, there were no effects on systolic pressure, diastolic pressure, or mean arterial pressure. As to quantitative changes related to physical exercise, the main findings were a 21% increase in the fractional volume occupied by neurons in the SG, and an 83% increase in the mean perikaryal volume of SG neurons in treadmill-trained rats, which shows a remarkable neuron hypertrophy. It seems reasonable to infer that neuron hypertrophy may have been the result of a functional overload imposed on the SG neurons by initial posttraining sympathetic activation. From the novel stereological data we provide, further investigations are needed to shed light on the mechanistic aspect of neuron hypertrophy: what role does neuron hypertrophy play? Could neuron hypertrophy be assigned to the functional overload induced by physical exercise?

Exercise reduces inhibitory neuroactivity and protects myenteric neurons from age-related neurodegeneration.

The practice of regular exercise is indicated to prevent some motility disturbances in the gastrointestinal tract, such as constipation, during aging. The motility alterations are intimately linked with its innervations. The goal of this study is to determine whether a program of exercise (running on the treadmill), during 6 months, has effects in the myenteric neurons (NADH- and NADPH-diaphorase stained neurons) in the colon of rats during aging. Male Wistar rats 6 months (adult) and 12 months (middle-aged) old were divided into 3 different groups: AS (adult sedentary), MS (middle-aged sedentary) and MT (middle-aged submitted to physical activity). The aging did not cause a decline significant (p>0.05) of the number of NADH-diaphorase stained neurons in sedentary rats (AS vs. MS group). In contrast, a decline of 31% was observed to NADPH-diaphorase stained neurons. Thus, animals that underwent physical activity (AS vs. MT group) rescued neurons from degeneration caused by aging (total number, density and profile of neurons did not change with age--NADH-diaphorase method). On the other hand, physical activity augmented the decline of NADPH-diaphorase positive neurons (total number, density and profile of neurons decreased). Collectively, the results show that exercise inhibits age-related decline of myenteric neurons however, exercise augments the decline of neurons with inhibitory activity (nitric oxide) in the colon of the rats.

Balanced Caloric Restriction Minimizes Changes Caused by Aging on the Colonic Myenteric Plexus.

Aging can promote significant morphofunctional changes in the gastrointestinal tract (GIT). Regulation of GIT motility is mainly controlled by the myenteric neurons of the enteric nervous system. Actions that aim at decreasing the aging effects in the GIT include those related to diet, with caloric restriction (CR). The CR is achieved by controlling the amount of food or by manipulating the components of the diet. Therefore, the objective of this study was to evaluate different levels of CR on the plasticity of nicotinamide adenine dinucleotide phosphate- (NADPH-) reactive myenteric neurons in the colon of Wistar rats during the aging process using ultrastructural (transmission electron microscopy) and morphoquantitative analysis. Wistar male rats (Rattus norvegicus) were distributed into 4 groups (n = 10/group): C, 6-month-old animals; SR, 18-month-old animals fed a normal diet; CRI, 18-month-old animals fed a 12% CR diet; CRII, 18-month-old animals fed a 31% CR diet. At 6 months of age, animals were transferred to the laboratory animal facility, where they remained until 18 months of age. Animals of the CRI and CRII groups were submitted to CR for 6 months. In the ultrastructural analysis, a disorganization of the periganglionar matrix with the aging was observed, and this characteristic was not observed in the animals that received hypocaloric diet. It was observed that the restriction of 12.5% and 31% of calories in the diet minimized the increase in density and cell profile of the reactive NADPH neurons, increased with age. This type of diet may be adapted against gastrointestinal disturbances that commonly affect aging individuals.

Positive changes in femoral nerve morphometry in older rats following aerobic training.

The objective of the present study was to analyze alterations of the femoral nerve of aged rats subjected to aerobic training. Wistar rats (12-mo of age) were divided in to two groups: S group (sedentary) and T group (trained). The exercise protocol were 16 weeks long. The groups were sacrificed at 16 months. Ultrafine sections of the femoral nerve have been used. There was no change in the body weight between the groups. T group showed a significant increase in myelinated fiber area, axon diameter, myelin sheath thickness and myelin fiber number compared with sedentary controls. In exercised trained animals, histograms of the frequency distribution of myelinated axons according to their areas showed increased number of medium and large fibers in relation to small fibers, which decreased in number. Aerobic training animals, showed the distribution of myelinated fiber population according to their area being bimodal, with the distribution shifted to the right, indicating increased fiber area. The T group showed a percent damage of large myelinated fibers significantly lower compared to controls. No significant difference was observed between the groups for the g-ratio. The T group also showed a significant increase in the number of microtubules and neurofilaments in myelinated fibers, which was not observed in S group. In conclusion, aerobic training improves nerve structure without evidence of nerve damage and produces an attenuation on the modifications in femoral nerve that develop in old age.