Effects of aerobic exercise on chronic allergic airway inflammation and remodeling in guinea pigs

We evaluated the effects of aerobic exercise (AE) on airway inflammation, exhaled nitric oxide levels (ENO), airway remodeling, and the expression of Thl, Th2 and regulatory cytokines in a guinea pig asthma model. Animals were divided into 4 groups: non-trained and non-sensitized (C), non-sensitized and AE (AE), ovalbumin-sensitized and non-trained (OVA), and OVA-sensitized and AE (OVA + AE). OVA inhalation was performed for 8 weeks, and AE was conducted for 6 weeks beginning in the 3rd week of OVA sensitization. Compared to the other groups, the OVA + AE group had a reduced density of eosinophils and lymphocytes, reduced expression of interleukin (IL)-4 and IL-13 and an increase in epithelium thickness (p < 0.05). AE did not modify airway remodeling or ENO in the sensitized groups (p > 0.05). Neither OVA nor AE resulted in differences in the expression of IL-2, IFN-gamma, IL-10 or IL1-ra. Our results show that AE reduces the expression of Th2 cytokines and allergic airway inflammation and induces epithelium remodeling in sensitized guinea pigs. (c) 2012 Elsevier B.V. All rights reserved.

Intermittent hypoxia inhibits clearance of triglyceride-rich lipoproteins and inactivates adipose lipoprotein lipase in a mouse model of sleep apnoea

Delayed lipoprotein clearance is associated with atherosclerosis. This study examined whether chronic intermittent hypoxia (CIH), a hallmark of obstructive sleep apnoea (OSA), can lead to hyperlipidaemia by inhibiting clearance of triglyceride rich lipoproteins (TRLP). Male C57BL/6J mice on high-cholesterol diet were exposed to 4 weeks of CIH or chronic intermittent air (control). FIO2 was decreased to 6.5 once per minute during the 12 h light phase in the CIH group. After the exposure, we measured fasting lipid profile. TRLP clearance was assessed by oral gavage of retinyl palmitate followed by serum retinyl esters (REs) measurements at 0, 1, 2, 4, 10, and 24 h. Activity of lipoprotein lipase (LpL), a key enzyme of lipoprotein clearance, and levels of angiopoietin-like protein 4 (Angptl4), a potent inhibitor of the LpL activity, were determined in the epididymal fat pads, skeletal muscles, and heart. Chronic intermittent hypoxia induced significant increases in levels of total cholesterol and triglycerides, which occurred in TRLP and LDL fractions (P 0.05 for each comparison). Compared with control mice, animals exposed to CIH showed increases in REs throughout first 10 h after oral gavage of retinyl palmitate (P 0.05), indicating that CIH inhibited TRLP clearance. CIH induced a 5-fold decrease in LpL activity (P 0.01) and an 80 increase in Angptl4 mRNA and protein levels in the epididymal fat, but not in the skeletal muscle or heart. CIH decreases TRLP clearance and inhibits LpL activity in adipose tissue, which may contribute to atherogenesis observed in OSA.

Chronic VEGF Blockade Worsens Glomerular Injury in the Remnant Kidney Model

VEGF inhibition can promote renal vascular and parenchymal injury, causing proteinuria, hypertension and thrombotic microangiopathy. The mechanisms underlying these side effects are unclear. We investigated the renal effects of the administration, during 45 days, of sunitinib (Su), a VEGF receptor inhibitor, to rats with 5/6 renal ablation (Nx). Adult male Munich-Wistar rats were distributed among groups S+V, sham-operated rats receiving vehicle only; S+Su, S rats given Su, 4 mg/kg/day; Nx+V, Nx rats receiving V; and Nx+Su, Nx rats receiving Su. Su caused no change in Group S. Seven and 45 days after renal ablation, renal cortical interstitium was expanded, in association with rarefaction of peritubular capillaries. Su did not worsen hypertension, proteinuria or interstitial expansion, nor did it affect capillary rarefaction, suggesting little angiogenic activity in this model. Nx animals exhibited glomerulosclerosis (GS), which was aggravated by Su. This effect could not be explained by podocyte damage, nor could it be ascribed to tuft hypertrophy or hyperplasia. GS may have derived from organization of capillary microthrombi, frequently observed in Group Nx+Su. Treatment with Su did not reduce the fractional glomerular endothelial area, suggesting functional rather than structural cell injury. Chronic VEGF inhibition has little effect on normal rats, but can affect glomerular endothelium when renal damage is already present.

Effects of selective bile duct ligation on liver parenchyma in young animals: histologic and molecular evaluations

Background/Purpose: The mechanisms of increased collagen production and liver parenchyma fibrosis are poorly understood. These phenomena are observed mainly in children with biliary obstruction (BO), and in a great number of patients, the evolution to biliary cirrhosis and hepatic failure leads to the need for liver transplantation before adolescence. However, pediatric liver transplantation presents with biliary complications in 20% to 30% of cases in the postoperative period. Intra-or extrahepatic stenosis of bile ducts is frequent and may lead to secondary biliary cirrhosis and the need for retransplantation. It is unknown whether biliary stenosis involving isolated segments or lobes may affect the adjacent nonobstructed lobes by paracrine or endocrine means, leading to fibrosis in this parenchyma. Therefore, the present study aimed to create an experimental model of selective biliary duct ligation in young animals with a subsequent evaluation of the histologic and molecular alterations in liver parenchyma of the obstructed and nonobstructed lobes. Methods: After a pilot study to standardize the surgical procedures, weaning rats underwent ligation of the bile ducts of the median, left lateral, and caudate liver lobes. The bile duct of the right lateral lobe was kept intact. To avoid intrahepatic biliary duct collaterals neoformation, the parenchymal connection between the right lateral and median lobes was clamped. The animals were divided into groups according to the time of death: 1, 2, 3, 4, and 8 weeks after surgical procedure. After death, the median and left lateral lobes (with BO) and the right lateral lobe (without BO [NBO]) were harvested separately. A group of 8 healthy nonoperated on animals served as controls. Liver tissues were subjected to histologic evaluation and quantification of the ductular proliferation and of the portal fibrosis. The expressions of smooth muscle alpha-actin (alpha-SMA), desmin, and transforming growth factor beta 1 genes were studied by molecular analyses (semiquantitative reverse transcriptase-polymerase chain reaction and real-time polymerase chain reaction, a quantitative method). Results: Histologic analyses revealed the occurrence of ductular proliferation and collagen formation in the portal spaces of both BO and NBO lobes. These phenomena were observed later in NBO than BO. Bile duct density significantly increased 1 week after duct ligation; it decreased after 2 and 3 weeks and then increased again after 4 and 8 weeks in both BO and NBO lobes. The portal space collagen area increased after 2 weeks in both BO and NBO lobes. After 3 weeks, collagen deposition in BO was even higher, and in NBO, the collagen area started decreasing after 2 weeks. Molecular analyses revealed increased expression of the alpha-SMA gene in both BO and NBO lobes. The semiquantitative and quantitative methods showed concordant results. Conclusions: The ligation of a duct responsible for biliary drainage of the liver lobe promoted alterations in the parenchyma and in the adjacent nonobstructed parenchyma by paracrine and/or endocrine means. This was supported by histologic findings and increased expression of alpha-SMA, a protein related to hepatic fibrogenesis. (C) 2012 Elsevier Inc. All rights reserved.

Effect of N-acetylcysteine on pulmonary cell death in a controlled hemorrhagic shock model in rats

PURPOSE: To evaluate the effect of N-acetylcysteine (NAC) combined with fluid resuscitation on pulmonary cell death in rats induced with controlled hemorrhagic shock (HS). METHODS: Two arteries (MAP calculation and exsanguination) and one vein (treatments) were catheterized in 22 anesthetized rats. Two groups of male albino rats were induced with controlled HS at 35mmHg MAP for 60 min. After this period, the RL group was resuscitated with Ringer's lactate and the RL+NAC group was resuscitated with Ringer's lactate combined with 150mg/Kg NAC. The control group animals were cannulated only. The animals were euthanized after 120 min of fluid resuscitation. Lung tissue samples were collected to evaluate the following: histopathology, TUNEL and imunohistochemical expression of caspase 3. RESULTS: RL showed a greater number of cells stained by TUNEL than RL + NAC, but there was no change in caspase 3 expression in any group. CONCLUSION: N-acetylcysteine associate to fluid resuscitation, after hemorrhagic shock, decreased cell death attenuating lung injury.

Study of using marker assisted selection on a beef cattle breeding program by model comparison

A data set of a commercial Nellore beef cattle selection program was used to compare breeding models that assumed or not markers effects to estimate the breeding values, when a reduced number of animals have phenotypic, genotypic and pedigree information available. This herd complete data set was composed of 83,404 animals measured for weaning weight (WW), post-weaning gain (PWG), scrotal circumference (SC) and muscle score (MS), corresponding to 116,652 animals in the relationship matrix. Single trait analyses were performed by MTDFREML software to estimate fixed and random effects solutions using this complete data. The additive effects estimated were assumed as the reference breeding values for those animals. The individual observed phenotype of each trait was adjusted for fixed and random effects solutions, except for direct additive effects. The adjusted phenotype composed of the additive and residual parts of observed phenotype was used as dependent variable for models' comparison. Among all measured animals of this herd, only 3160 animals were genotyped for 106 SNP markers. Three models were compared in terms of changes on animals' rank, global fit and predictive ability. Model 1 included only polygenic effects, model 2 included only markers effects and model 3 included both polygenic and markers effects. Bayesian inference via Markov chain Monte Carlo methods performed by TM software was used to analyze the data for model comparison. Two different priors were adopted for markers effects in models 2 and 3, the first prior assumed was a uniform distribution (U) and, as a second prior, was assumed that markers effects were distributed as normal (N). Higher rank correlation coefficients were observed for models 3_U and 3_N, indicating a greater similarity of these models animals' rank and the rank based on the reference breeding values. Model 3_N presented a better global fit, as demonstrated by its low DIC. The best models in terms of predictive ability were models 1 and 3_N. Differences due prior assumed to markers effects in models 2 and 3 could be attributed to the better ability of normal prior in handle with collinear effects. The models 2_U and 2_N presented the worst performance, indicating that this small set of markers should not be used to genetically evaluate animals with no data, since its predictive ability is restricted. In conclusion, model 3_N presented a slight superiority when a reduce number of animals have phenotypic, genotypic and pedigree information. It could be attributed to the variation retained by markers and polygenic effects assumed together and the normal prior assumed to markers effects, that deals better with the collinearity between markers. (C) 2012 Elsevier B.V. All rights reserved.

Early detection of doxorubicin myocardial injury by ultrasonic tissue characterization in an experimental animal model

In the clinical setting, the early detection of myocardial injury induced by doxorubicin (DXR) is still considered a challenge. To assess whether ultrasonic tissue characterization (UTC) can identify early DXR-related myocardial lesions and their correlation with collagen myocardial percentages, we studied 60 rats at basal status and prospectively after 2mg/Kg/week DXR endovenous infusion. Echocardiographic examinations were conducted at baseline and at 8,10,12,14 and 16 mg/Kg DXR cumulative dose. The left ventricle ejection fraction (LVEF), shortening fraction (SF), and the UTC indices: corrected coefficient of integrated backscatter (IBS) (tissue IBS intensity/phantom IBS intensity) (CC-IBS) and the cyclic variation magnitude of this intensity curve (MCV) were measured. The variation of each parameter of study through DXR dose was expressed by the average and standard error at specific DXR dosages and those at baseline. The collagen percent (%) was calculated in six control group animals and 24 DXR group animals. CC-IBS increased (1.29 +/- 0.27 x 1.1 +/- 0.26-basal; p=0.005) and MCV decreased (9.1 +/- 2.8 x 11.02 +/- 2.6-basal; p=0.006) from 8 mg/Kg to 16mg/Kg DXR. LVEF presented only a slight but significant decrease (80.4 +/- 6.9% x 85.3 +/- 6.9%-basal, p=0.005) from 8 mg/Kg to 16 mg/Kg DXR. CC-IBS was 72.2% sensitive and 83.3% specific to detect collagen deposition of 4.24%(AUC=0.76). LVEF was not accurate to detect initial collagen deposition (AUC=0.54). In conclusion: UTC was able to early identify the DXR myocardial lesion when compared to LVEF, showing good accuracy to detect the initial collagen deposition in this experimental animal model.

Proposal of non-invasive experimental model to induce scoliosis in rats

Background: In the literature, there are several experimental models that induce scoliosis in rats; however, they make use of drugs or invasive interventions to generate a scoliotic curve. Objectives: To design and apply a non-invasive immobilization model to induce scoliosis in rats. Methods: Four-week old male Wistar rats (85 +/- 3.3 g) were divided into two groups: control (CG) and scoliosis (SG). The animals in the SG were immobilized by two vests (scapular and pelvic) made from polyvinyl chloride (PVC) and externally attached to each other by a retainer that regulated the scoliosis angle for twelve weeks with left convexity. After immobilization, the abdominal, intercostal, paravertebral, and pectoral muscles were collected for chemical and metabolic analyses. Radiographic reports were performed every 30 days over a 16-week period. Results: The model was effective in the induction of scoliosis, even 30 days after immobilization, with a stable angle of 28 +/- 5 degrees. The chemical and metabolic analyses showed a decrease (p<0.05) in the glycogenic reserves and in the relationship between DNA and total protein reserves of all the muscles analyzed in the scoliosis group, being lower (p<0.05) in the convex side. The values for the Homeostatic Model Assessment of Insulin Resistance indicated a resistance condition to insulin (p<0.05) in the scoliosis group (0.66 +/- 0.03), when compared to the control group (0.81 +/- 0.02). Conclusions: The scoliosis curvature remained stable 30 days after immobilization. The chemical and metabolic analyses suggest changes in muscular homeostasis during the induced scoliosis process.

Biological evaluation of the bone healing process after application of two potentially osteogenic proteins: an animal experimental model

doi: 10.1111/j.1741-2358.2011.00526.x Biological evaluation of the bone healing process after application of two potentially osteogenic proteins: an animal experimental model Objective: The aim of this work was to analyse qualitatively and quantitatively the newly formed bone after insertion of rhBMP-2 and protein extracted from Hevea brasiliensis (P-1), associated or not with a carrier in critical bone defects created in Wistar rat calvarial bone, using histological and histomorphometrical analyses. Materials and methods: Eighty-four male Wistar rats were used, divided into two groups, according to the period of time until the sacrifice (2 and 6 weeks). Each one of these groups was subdivided into six groups with seven animals each, according to the treatments: (1) 5 mu g of pure rhBMP-2, (2) 5 mu g of rhBMP-2/monoolein gel, (3) pure monoolein gel, (4) 5 mu g of pure P-1, (5) 5 mu g of P-1/monoolein gel and (6) critical bone defect controls. The animals were euthanised and the calvarial bone tissue removed for histological and histomorphometrical analyses. Result and conclusion: The results showed an improvement in the bone healing process using the rhBMP-2 protein, associated or not with a material carrier in relation to the other groups, and this process demonstrated to be time dependent.

DEVELOPMENT OF AN EXPERIMENTAL MODEL OF INFECTED BONE VOID IN THE ULNA OF RABBITS

Objective: Develop a model that allowed the study of bone regeneration in infection conditions. Method: A 15 mm defect was surgically created in the rabbit ulna and inoculated with 5x10(8) colony-forming units (CFU) of S. aureus. Surgical debridement was performed two weeks after and systemic gentamicin was administered for four weeks. Animals were followed up to 12 weeks to evaluate infection control and bone regeneration. Result: Bone regeneration was inferior to 25% of the defect in radiological and histological analysis. Conclusion: Infected bone defect of 15 mm in the rabbit ulna was unable to achieve full regeneration without further treatment. Level of Evidence V, Experimental Study.

Human Fallopian Tube Mesenchymal Stromal Cells Enhance Bone Regeneration in a Xenotransplanted Model

We have recently reported that human fallopian tubes, which are discarded during surgical procedures of women submitted to sterilization or hysterectomies, are a rich source of human fallopian tube mesenchymal stromal cells (htMSCs). It has been previously shown that human mesenchymal stromal cells may be useful in enhancing the speed of bone regeneration. This prompted us to investigate whether htMSCs might be useful for the treatment of osteoporosis or other bone diseases, since they present a pronounced capacity for osteogenic differentiation in vitro. Based on this prior knowledge, our aim was to evaluate, in vivo, the osteogenic capacity of htMSCs to regenerate bone through an already described xenotransplantation model: nonimmunosuppressed (NIS) rats with cranial defects. htMSCs were obtained from five 30-50 years old healthy women and characterized by flow cytometry and for their multipotenciality in vitro capacity (osteogenic, chondrogenic and adipogenic differentiations). Two symmetric full-thickness cranial defects on each parietal region of seven NIS rats were performed. The left side (LS) of six animals was covered with CellCeram (Scaffdex)-a bioabsorbable ceramic composite scaffold that contains 60% hydroxyapatite and 40% beta-tricalciumphosphate-only, and the right side (RS) with the CellCeram and htMSCs (10(6) cells/scaffold). The animals were euthanized at 30, 60 and 90 days postoperatively and cranial tissue samples were taken for histological analysis. After 90 days we observed neobone formation in both sides. However, in animals euthanized 30 and 60 days after the procedure, a mature bone was observed only on the side with htMSCs. PCR and immunofluorescence analysis confirmed the presence of human DNA and thus that human cells were not rejected, which further supports the imunomodulatory property of htMSCs. In conclusion, htMSCs can be used successfully to enhance bone regeneration in vivo, opening a new field for future treatments of osteoporosis and bone reconstruction.

Previous Exercise Training Has a Beneficial Effect on Renal and Cardiovascular Function in a Model of Diabetes

Exercise training (ET) is an important intervention for chronic diseases such as diabetes mellitus (DM). However, it is not known whether previous exercise training intervention alters the physiological and medical complications of these diseases. We investigated the effects of previous ET on the progression of renal disease and cardiovascular autonomic control in rats with streptozotocin (STZ)-induced DM. Male Wistar rats were divided into five groups. All groups were followed for 15 weeks. Trained control and trained diabetic rats underwent 10 weeks of exercise training, whereas previously trained diabetic rats underwent 14 weeks of exercise training. Renal function, proteinuria, renal sympathetic nerve activity (RSNA) and the echocardiographic parameters autonomic modulation and baroreflex sensitivity (BRS) were evaluated. In the previously trained group, the urinary albumin/creatinine ratio was reduced compared with the sedentary diabetic and trained diabetic groups (p < 0.05). Additionally, RSNA was normalized in the trained diabetic and previously trained diabetic animals (p < 0.05). The ejection fraction was increased in the previously trained diabetic animals compared with the diabetic and trained diabetic groups (p < 0.05), and the myocardial performance index was improved in the previously trained diabetic group compared with the diabetic and trained diabetic groups (p < 0.05). In addition, the previously trained rats had improved heart rate variability and BRS in the tachycardic response and bradycardic response in relation to the diabetic group (p < 0.05). This study demonstrates that previous ET improves the functional damage that affects DM. Additionally, our findings suggest that the development of renal and cardiac dysfunction can be minimized by 4 weeks of ET before the induction of DM by STZ.

Forced Desynchronization of Activity Rhythms in a Model of Chronic Jet Lag in Mice

We studied locomotor activity rhythms of C57/Bl6 mice under a chronic jet lag (CJL) protocol (ChrA(6/2)), which consisted of 6-hour phase advances of the light-dark schedule (LD) every 2 days. Through periodogram analysis, we found 2 components of the activity rhythm: a short-period component (21.01 +/- 0.04 h) that was entrained by the LD schedule and a long-period component (24.68 +/- 0.26 h). We developed a mathematical model comprising 2 coupled circadian oscillators that was tested experimentally with different CJL schedules. Our simulations suggested that under CJL, the system behaves as if it were under a zeitgeber with a period determined by (24 -[phase shift size/days between shifts]). Desynchronization within the system arises according to whether this effective zeitgeber is inside or outside the range of entrainment of the oscillators. In this sense, ChrA(6/2) is interpreted as a (24 - 6/2 = 21 h) zeitgeber, and simulations predicted the behavior of mice under other CJL schedules with an effective 21-hour zeitgeber. Animals studied under an asymmetric T = 21 h zeitgeber (carried out by a 3-hour shortening of every dark phase) showed 2 activity components as observed under ChrA(6/2): an entrained short-period (21.01 +/- 0.03 h) and a long-period component (23.93 +/- 0.31 h). Internal desynchronization was lost when mice were subjected to 9-hour advances every 3 days, a possibility also contemplated by the simulations. Simulations also predicted that desynchronization should be less prevalent under delaying than under advancing CJL. Indeed, most mice subjected to 6-hour delay shifts every 2 days (an effective 27-hour zeitgeber) displayed a single entrained activity component (26.92 +/- 0.11 h). Our results demonstrate that the disruption provoked by CJL schedules is not dependent on the phase-shift magnitude or the frequency of the shifts separately but on the combination of both, through its ratio and additionally on their absolute values. In this study, we present a novel model of forced desynchronization in mice under a specific CJL schedule; in addition, our model provides theoretical tools for the evaluation of circadian disruption under CJL conditions that are currently used in circadian research.

Imunocompetent Mice Model for Dengue Virus Infection

Dengue fever is a noncontagious infectious disease caused by dengue virus (DENV). DENV belongs to the family Flaviviridae, genus Flavivirus, and is classified into four antigenically distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. The number of nations and people affected has increased steadily and today is considered the most widely spread arbovirus (arthropod-borne viral disease) in the world. The absence of an appropriate animal model for studying the disease has hindered the understanding of dengue pathogenesis. In our study, we have found that immunocompetent C57BL/6 mice infected intraperitoneally with DENV-1 presented some signs of dengue disease such as thrombocytopenia, spleen hemorrhage, liver damage, and increase in production of IFN gamma and TNF alpha cytokines. Moreover, the animals became viremic and the virus was detected in several organs by real-time RT-PCR. Thus, this animal model could be used to study mechanism of dengue virus infection, to test antiviral drugs, as well as to evaluate candidate vaccines.

Hyperbaric Oxygen Therapy Induces Kidney Protection in an Ischemia/Reperfusion Model in Rats

Ischemia/reperfusion (I/R) injury remains a major cause of graft dysfunction, which impacts short- and long-term follow-up. Hyperbaric oxygen therapy (HBO), through plasma oxygen transport, has been currently used as an alternative treatment for ischemic tissues. The aim of this study was to analyze the effects of HBO on kidney I/R injury model in rats, in reducing the harmful effect of I/R. The renal I/R model was obtained by occluding bilateral renal pedicles with nontraumatic vascular clamps for 45 minutes, followed by 48 hours of reperfusion. HBO therapy was delivered an hypebaric chamber (2.5 atmospheres absolute). Animals underwent two sessions of 60 minutes each at 6 hours and 20 hours after initiation of reperfusion. Male Wistar rats (n = 38) were randomized into four groups: sham, sham operated rats; Sham+HBO, sham operated rats exposed to HBO; I/R, animals submitted to I/R; and I/R+HBO, I/R rats exposed to HBO. Blood, urine, and kidney tissue were collected for biochemical, histologic, and immunohistochemical analyses. The histopathological evaluation of the ischemic injury used a grading scale of 0 to 4. HBO attenuated renal dysfunction after ischemia characterized by a significant decrease in blood urea nitrogen (BUN), serum creatinine, and proteinuria in the I/R+HBO group compared with I/R alone. In parallel, tubular function was improved resulting in significantly lower fractional excretions of sodium and potassium. Kidney sections from the I/R plus HBO group showed significantly lower acute kidney injury scores compared with the I/R group. HBO treatment significantly diminished proliferative activity in I/R (P < .05). There was no significant difference in macrophage infiltration or hemoxygenase-1 expression. In conclusion, HBO attenuated renal dysfunction in a kidney I/R injury model with a decrease in BUN, serum creatinine, proteinuria, and fractional excretion of sodium and potassium, associated with reduced histological damage.