N-Acetylcysteine protects the peritoneum from the injury induced by hypertonic dialysis solution

Background: Oxidative stress has been implicated in the development of peritoneal damage. The aim of this study was to evaluate the effects of N-acetylcysteine (NAC) in a rat peritoneal infusion model. Methods: Eighteen male Wistar rats were divided in 3 groups: (i) control group; (ii) HDS group, receiving peritoneal dialysis solution (PDS); and (iii) HDS+NAC group, receiving PDS and oral NAC. Six weeks later they were evaluated for dialysate to plasma urea ratio (D/P), ratio of glucose concentration in peritoneal fluid (G1/G0), thiobarbituric acid reactive substances in plasma and urine and histology of peritoneal membrane. Results: The HDS+NAC group presented a lower increase in solute transport (D/P 0.51 +/- 0.1, and G1/GO 0.35 +/- 0.06) in comparison with the HDS group (D/P 0.67 +/- 0.1; p=0.03, and G1/G0 0.27 +/- 0.07; p=0.01). The HDS+NAC group showed lower thiobarbituric acid reactive substance concentrations compared with the HDS group. In the treated group, the peritoneal membrane presented lower thickness. Conclusions: Functional and histological peritoneal changes were significantly reduced by the treatment with NAC.

Effect of Colchicine on Myocardial Injury Induced by Trypanosoma cruzi in Experimental Chagas Disease

Background: The hallmark of Chagas disease (CD) is multifocal myocarditis and extensive fibrosis. We investigated the potential effect of colchicine on myocardial remodeling in experimental CD. Methods and Results: One hundred Syrian hamsters were randomly divided into noninfected untreated control (CG), noninfected control treated with colchicine (COLG 0.4 mg kg(-1) d(-1) by gavage), infected (IG), and infected treated with colchicine (ICOLG, 0.4 mg kg(-1) d(-1)) groups. The interstitial collagen volume fraction (ICVF) was evaluated by videomorphometry with picrosirius red staining. The gelatinolytic activities of matrix metalloproteinase (MMP) 2 were examined with the use of zymography. Myocarditis was described according to the Dallas criteria. Statistical comparisons were performed with parametric analysis of variance and Tukey test. ICVF (%) accumulation was attenuated in infected colchicine-treated animals in the left (CG 0.81 +/- 0.13, COLG 0.85 +/- 0.13, IG: 1.35 +/- 0.31,* ICOLG 1.06 +/- 0.19; *P < .05 compared with ICOLG) and right ventricles (CG 1.4 +/- 0.36, COLG 1.26 +/- 0.14, IG 1.97 +/- 0.058,* ICOLG: 1.52 +/- 0.23; *P < .05 compared with ICOLG). A significant increase in MMP-2 enzymatic activity (UA) was observed in ICOLG (17,432.8*) compared with GC (3731.6), COLG (2,792.6), and IG (4,286.3; *P < .001). In IG, 66% of animals had myocarditis compared with only 49% in ICOLG. Conclusions: Colchicine had a protective effect on myocardium, indicated by decreased interstitial myocardial fibrosis, increased intensity of MMP-2, and attenuated myocardial inflammation. (J Cardiac Fail 2012;18:654-659)

TLR2, TLR4 and the MYD88 Signaling Pathway Are Crucial for Neutrophil Migration in Acute Kidney Injury Induced by Sepsis

The aim of this study was to investigate the role of TLR2, TLR4 and MyD88 in sepsis-induced AKI. C57BL/6 TLR2(-/-), TLR4(-/-) and MyD88(-/-) male mice were subjected to sepsis by cecal ligation and puncture (CLP). Twenty four hours later, kidney tissue and blood samples were collected for analysis. The TLR2(-/-), TLR4(-/-) and MyD88(-/-) mice that were subjected to CLP had preserved renal morphology, and fewer areas of hypoxia and apoptosis compared with the wild-type C57BL/6 mice (WT). MyD88(-/-) mice were completely protected compared with the WT mice. We also observed reduced expression of proinflammatory cytokines in the kidneys of the knockout mice compared with those of the WT mice and subsequent inhibition of increased vascular permeability in the kidneys of the knockout mice. The WT mice had increased GR1(+low) cells migration compared with the knockout mice and decreased in GR1(+high) cells migration into the peritoneal cavity. The TLR2(-/-), TLR4(-/-), and MyD88(-/-) mice had lower neutrophil infiltration in the kidneys. Depletion of neutrophils in the WT mice led to protection of renal function and less inflammation in the kidneys of these mice. Innate immunity participates in polymicrobial sepsis-induced AKI, mainly through the MyD88 pathway, by leading to an increased migration of neutrophils to the kidney, increased production of proinflammatory cytokines, vascular permeability, hypoxia and apoptosis of tubular cells.

Aerobic exercise attenuates pulmonary injury induced by exposure to cigarette smoke

It has recently been suggested that regular exercise reduces lung function decline and risk of chronic obstructive pulmonary disease (COPD) among active smokers; however, the mechanisms involved in this effect remain poorly understood. The present study evaluated the effects of regular exercise training in an experimental mouse model of chronic cigarette smoke exposure. Male C57BL/6 mice were divided into four groups (control, exercise, smoke and smoke+exercise). For 24 weeks, we measured respiratory mechanics, mean linear intercept, inflammatory cells and reactive oxygen species (ROS) in bronchoalveolar lavage (BAL) fluid, collagen deposition in alveolar walls, and the expression of antioxidant enzymes, matrix metalloproteinase 9, tissue inhibitor of metalloproteinase (TIMP) 1, interleukin (IL)-10 and 8-isoprostane in alveolar walls. Exercise attenuated the decrease in pulmonary elastance (p<0.01) and the increase in mean linear intercept (p=0.003) induced by cigarette smoke exposure. Exercise substantially inhibited the increase in ROS in BAL fluid and 8-isoprostane expression in lung tissue induced by cigarette smoke. In addition, exercise significantly inhibited the decreases in IL-10, TIMP1 and CuZn superoxide dismutase induced by exposure to cigarette smoke. Exercise also increased the number of cells expressing glutathione peroxidase. Our results suggest that regular aerobic physical training of moderate intensity attenuates the development of pulmonary disease induced by cigarette smoke exposure.

Coffee and Caffeine Protect against Liver Injury Induced by Thioacetamide in Male Wistar Rats

Coffee intake has been inversely related to the incidence of liver diseases, although there are controversies on whether these beneficial effects on human health are because of caffeine or other specific components in this popular beverage. Thus, this study evaluated the protective effects of coffee or caffeine intake on liver injury induced by repeated thioacetamide (TAA) administration in male Wistar rats. Rats were randomized into five groups: one untreated group (G1) and four groups (G2G5) treated with the hepatotoxicant TAA (200 similar to mg/kg b.w., i.p.) twice a week for 8 similar to weeks. Concomitantly, rats received tap water (G1 and G2), conventional coffee (G3), decaffeinated coffee (G4) or 0.1% caffeine (G5). After 8 similar to weeks of treatment, rats were killed and blood and liver samples were collected. Conventional and decaffeinated coffee and caffeine intake significantly reduced serum levels of alanine aminotransferase (ALT) (p similar to<similar to 0.001) and oxidized glutathione (p similar to<similar to 0.05), fibrosis/inflammation scores (p similar to<similar to 0.001), collagen volume fraction (p similar to<similar to 0.01) and transforming growth factor beta-1 (TGF-beta 1) protein expression (p similar to=similar to 0.001) in the liver from TAA-treated groups. In addition, conventional coffee and caffeine intake significantly reduced proliferating cellular nuclear antigen (PCNA) S-phase indexes (p similar to<similar to 0.001), but only conventional coffee reduced cleaved caspase-3 indexes (p similar to<similar to 0.001), active metalloproteinase 2 (p similar to=similar to 0.004) and the number of glutathione S-transferase placental form (GST-P)-positive preneoplastic lesions (p similar to<similar to 0.05) in the liver from TAA-treated groups. In conclusion, conventional coffee and 0.1% caffeine intake presented better beneficial effects than decaffeinated coffee against liver injury induced by TAA in male Wistar rats.

Interstrain differences in the severity of liver injury induced by a choline- and folate-deficient diet in mice are associated with dysregulation of genes involved in lipid metabolism

Nonalcoholic fatty liver disease (NAFLD) is a major health problem and a leading cause of chronic liver disease in the United States and developed countries. In humans, genetic factors greatly influence individual susceptibility to NAFLD. The goals of this study were to compare the magnitude of interindividual differences in the severity of liver injury induced by methyl-donor deficiency among individual inbred strains of mice and to investigate the underlying mechanisms associated with the variability. Feeding mice a choline-and folate-deficient diet for 12 wk caused liver injury similar to NAFLD. The magnitude of liver injury varied among the strains, with the order of sensitivity being A/J approximate to C57BL/6J approximate to C3H/HeJ < 129S1/SvImJ approximate to CAST/EiJ < PWK/PhJ < WSB/EiJ. The interstrain variability in severity of NAFLD liver damage was associated with dysregulation of genes involved in lipid metabolism, primarily with a down-regulation of the peroxisome proliferator receptor alpha (PPAR alpha)-regulated lipid catabolic pathway genes. Markers of oxidative stress and oxidative stress-induced DNA damage were also elevated in the livers but were not correlated with severity of liver damage. These findings suggest that the PPAR alpha-regulated metabolism network is one of the key mechanisms determining interstrain susceptibility and severity of NAFLD in mice.-Tryndyak, V., de Conti, A., Kobets, T., Kutanzi, K., Koturbash, I., Han, T., Fuscoe, J. C., Latendresse, J. R., Melnyk, S., Shymonyak, S., Collins, L., Ross, S. A., Rusyn, I., Beland, F. A., Pogribny, I. P. Interstrain differences in the severity of liver injury induced by a choline-and folate-deficient diet in mice are associated with dysregulation of genes involved in lipid metabolism. FASEB J. 26, 4592-4602 (2012). www.fasebj.org

Immunohistochemical evidence for myofibroblastlike cells associated with liver injury induced by Aflatoxin B1 in rainbow trout (Oncorhynchus mykiss)

In mammalian species, profibrogenic cells are activated to become myofibroblasts in response to liver damage. Few studies have examined hepatic myofibroblasts and their role in liver damage in teleosts. The aim of the present study was to investigate the involvement of myofibroblast-like cells in rainbow trout (Oncorhynchus mykiss) with hepatic damage induced by aflatoxin B1 (AFB1). Histopathological and immunohistochemical analyses characterized alterations in the liver stroma during the carcinogenic process. Anti-human a-smoothmuscle actin (SMA) and anti-human desmin primary antibodies were used in immunohistochemistry. Only the anti-SMA reagent labelled cells in trout liver. In the livers of control fish, only smooth muscle in blood vessels and around bile ducts was labelled. In the livers from AFB1-treated fish, SMA-positive cells were present in the stroma surrounding neoplastic lesions and in areas of desmoplastic reaction. These observations indicate that in teleosts, as in mammals, the myofibroblast-like cell is involved in fibrosis associated with liver injury. Chronic liver injury induced in trout by aflatoxin may provide a useful model system for study of the evolution of such mechanisms.

Protective effects of aerobic exercise on acute lung injury induced by LPS in mice

Abstract Introduction The regular practice of physical exercise has been associated with beneficial effects on various pulmonary conditions. We investigated the mechanisms involved in the protective effect of exercise in a model of lipopolysaccharide (LPS)-induced acute lung injury (ALI). Methods Mice were divided into four groups: Control (CTR), Exercise (Exe), LPS, and Exercise + LPS (Exe + LPS). Exercised mice were trained using low intensity daily exercise for five weeks. LPS and Exe + LPS mice received 200 µg of LPS intratracheally 48 hours after the last physical test. We measured exhaled nitric oxide (eNO); respiratory mechanics; neutrophil density in lung tissue; protein leakage; bronchoalveolar lavage fluid (BALF) cell counts; cytokine levels in BALF, plasma and lung tissue; antioxidant activity in lung tissue; and tissue expression of glucocorticoid receptors (Gre). Results LPS instillation resulted in increased eNO, neutrophils in BALF and tissue, pulmonary resistance and elastance, protein leakage, TNF-alpha in lung tissue, plasma levels of IL-6 and IL-10, and IL-1beta, IL-6 and KC levels in BALF compared to CTR (P ≤0.02). Aerobic exercise resulted in decreases in eNO levels, neutrophil density and TNF-alpha expression in lung tissue, pulmonary resistance and elastance, and increased the levels of IL-6, IL-10, superoxide dismutase (SOD-2) and Gre in lung tissue and IL-1beta in BALF compared to the LPS group (P ≤0.04). Conclusions Aerobic exercise plays important roles in protecting the lungs from the inflammatory effects of LPS-induced ALI. The effects of exercise are mainly mediated by the expression of anti-inflammatory cytokines and antioxidants, suggesting that exercise can modulate the inflammatory-anti-inflammatory and the oxidative-antioxidative balance in the early phase of ALI.

Unsecured intracranial aneurysms and induced hypertension in cerebral vasospasm: is induced hypertension safe?

Induced hypertension is an established therapy to treat cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH) to prevent delayed ischemic deficits. Currently, there is minimal evidence available assessing the risk of induced hypertension in the presence of unsecured aneurysms. The aim of this study was to investigate the impact of induced hypertension on the rupturing of unsecured aneurysms in treating CVS.

Intravital microscopy reveals endothelial dysfunction in resistance arterioles in Angiotensin II-induced hypertension

It is known that hypertension is associated with endothelial dysfunction and that Angiotensin II (Ang II) is a key player in the pathogenesis of hypertension. We aimed to elucidate whether endothelial dysfunction is a specific feature of Ang II-mediated hypertension or a common finding of hypertension, independently of underlying etiology. We studied endothelial-dependent vasorelaxation in precapillary resistance arterioles and in various large-caliber conductance arteries in wild-type mice with Ang II-dependent hypertension (2-kidney 1-clip (2K1C) model) or Ang II-independent (volume overload) hypertension (1-kidney 1-clip model (1K1C)). Normotensive sham mice were used as controls. Aortic mechanical properties were also evaluated. Intravital microscopy of precapillary arterioles revealed a significantly impaired endothelium-dependent vasorelaxation in 2K1C mice compared with sham mice, as quantified by the ratio of acetylcholine (ACh)-induced over S-nitroso-N-acetyl-D,L-penicillamine (SNAP)-induced vasorelaxation (2K1C: 0.49±0.12 vs. sham: 0.87±0.11, P=0.018). In contrast, the ACh/SNAP ratio in volume-overload hypertension 1K1C mice was not significantly different from sham mice, indicating no specific endothelial dysfunction (1K1C: 0.77±0.27 vs. sham: 0.87±0.11, P=0.138). Mechanical aortic wall properties and endothelium-dependent vasorelaxation, assessed ex vivo in rings of large-caliber conductance (abdominal and thoracic aorta, carotid and femoral arteries), were not different between 2K1C, 1K1C and sham mice. Endothelial dysfunction is an early feature of Ang II- but not volume-overload-mediated hypertension. This occurs exclusively at the level of precapillary arterioles and not in conduit arteries. Our findings, if confirmed in clinical studies, will provide a better understanding of the pathophysiological mechanisms of hypertension.

Norepinephrine-induced hypertension dilates vasospastic basilar artery after subarachnoid haemorrhage in rabbits

BACKGROUND: Vasopressor-induced hypertension is routinely indicated for prevention and treatment of cerebral vasospasm (CVS) after subarachnoid haemorrhage (SAH). Mechanisms underlying patients' clinical improvement during vasopressor-induced hypertension remain incompletely understood. The aim of this study was to evaluate angiographic effects of normovolaemic Norepinephrine (NE)-induced hypertension therapy on the rabbit basilar artery (BA) after SAH. METHODS: Cerebral vasospasm was induced using the one-haemorrhage rabbit model; sham-operated animals served as controls. Five days later the animals underwent follow-up angiography prior to and during NE-induced hypertension. Changes in diameter of the BA were digitally calculated in mean microm +/- SEM (standard error of mean). FINDINGS: Significant CVS of 14.2% was documented in the BA of the SAH animals on day 5 compared to the baseline angiogram on day 0 (n = 12, p < 0.01), whereas the BA of the control animals remained statistically unchanged (n = 12, p > 0.05). During systemic administration of NE, mean arterial pressure increased from 70.0 +/- 1.9 mmHg to 136.0 +/- 2.1 mmHg in the SAH group (n = 12, p < 0.001) and from 72.0 +/- 3.1 to 137.8 +/- 1.3 in the control group (n = 12, p < 0.001). On day 5 after SAH, a significant dilatation of the BA in response to norepinephrine could be demonstrated in both groups. The diameter of the BA in the SAH group increased from 640.5 +/- 17.5 microm to 722.5 +/- 23.7 microm (n = 12, p < 0.05; ). In the control group the diameter increased from 716.8 +/- 15.5 microm to 779.9 +/- 24.1 microm (n = 12, p < 0.05). CONCLUSION: This study demonstrated that NE-induced hypertension causes angiographic dilatation of the BA in the SAH rabbit model. Based on these observations, it can be hypothesised that clinical improvement during vasopressor-induced hypertension therapy after SAH might be explained with cerebral vasodilatation mechanisms that lead to improvement of cerebral blood flow.

Macrophage-independent T cell infiltration to the site of injury-induced brain inflammation

We have addressed the role of macrophages in glial response and T cell entry to the CNS after axonal injury, by using intravenous injection of clodronate-loaded mannosylated liposomes, in C57BL6 mice. As expected, clodronate-liposome treatment resulted in depletion of peripheral macrophages which was confirmed by F4/80- and MOMA-1(-) stainings in spleen. Sequential clodronate-liposome treatment 4, 2 and 0 days before axotomy resulted in significant reduction of infiltrating CD45(high) CD11b+ macrophages in the hippocampus at 1, 2 and 3 days post-lesion, measured by flow cytometry. There was a slight delay in the expansion of CD45(dim) CD11+ microglia in clodronate-liposome treated mice, but macrophage depletion had no effect on the percentage of infiltrating T cells in the lesion-reactive hippocampus. Lesion-induced TNFalpha mRNA expression was not affected by macrophage depletion, suggesting that activated glial cells are the primary source of this cytokine in the axonal injury-reactive brain. This identifies a potentially important distinction from inflammatory autoimmune infiltration in EAE, where macrophages are a prominent source of TNFalpha and their depletion prevents parenchymal T cell infiltration and disease.

Effect of indomethacin on bile acid-phospholipid interactions: implication for small intestinal injury induced by nonsteroidal anti-inflammatory drugs.

The injurious effect of nonsteroidal anti-inflammatory drugs (NSAIDs) in the small intestine was not appreciated until the widespread use of capsule endoscopy. Animal studies found that NSAID-induced small intestinal injury depends on the ability of these drugs to be secreted into the bile. Because the individual toxicity of amphiphilic bile acids and NSAIDs directly correlates with their interactions with phospholipid membranes, we propose that the presence of both NSAIDs and bile acids alters their individual physicochemical properties and enhances the disruptive effect on cell membranes and overall cytotoxicity. We utilized in vitro gastric AGS and intestinal IEC-6 cells and found that combinations of bile acid, deoxycholic acid (DC), taurodeoxycholic acid, glycodeoxycholic acid, and the NSAID indomethacin (Indo) significantly increased cell plasma membrane permeability and became more cytotoxic than these agents alone. We confirmed this finding by measuring liposome permeability and intramembrane packing in synthetic model membranes exposed to DC, Indo, or combinations of both agents. By measuring physicochemical parameters, such as fluorescence resonance energy transfer and membrane surface charge, we found that Indo associated with phosphatidylcholine and promoted the molecular aggregation of DC and potential formation of larger and isolated bile acid complexes within either biomembranes or bile acid-lipid mixed micelles, which leads to membrane disruption. In this study, we demonstrated increased cytotoxicity of combinations of bile acid and NSAID and provided a molecular mechanism for the observed toxicity. This mechanism potentially contributes to the NSAID-induced injury in the small bowel.

Blocking brain-derived neurotrophic factor inhibits injury-induced hyperexcitability of hippocampal CA3 neurons

Brain trauma can disrupt synaptic connections, and this in turn can prompt axons to sprout and form new connections. If these new axonal connections are aberrant, hyperexcitability can result. It has been shown that ablating tropomyosin-related kinase B (TrkB), a receptor for brain-derived neurotrophic factor (BDNF), can reduce axonal sprouting after hippocampal injury. However, it is unknown whether inhibiting BDNF-mediated axonal sprouting will reduce hyperexcitability. Given this, our purpose here was to determine whether pharmacologically blocking BDNF inhibits hyperexcitability after injury-induced axonal sprouting in the hippocampus. To induce injury, we made Schaffer collateral lesions in organotypic hippocampal slice cultures. As reported by others, we observed a 50% reduction in axonal sprouting in cultures treated with a BDNF blocker (TrkB-Fc) 14 days after injury. Furthermore, lesioned cultures treated with TrkB-Fc were less hyperexcitable than lesioned untreated cultures. Using electrophysiology, we observed a two-fold decrease in the number of CA3 neurons that showed bursting responses after lesion with TrkB-Fc treatment, whereas we found no change in intrinsic neuronal firing properties. Finally, evoked field excitatory postsynaptic potential recordings indicated an increase in network activity within area CA3 after lesion, which was prevented with chronic TrkB-Fc treatment. Taken together, our results demonstrate that blocking BDNF attenuates injury-induced hyperexcitability of hippocampal CA3 neurons. Axonal sprouting has been found in patients with post-traumatic epilepsy. Therefore, our data suggest that blocking the BDNF-TrkB signaling cascade shortly after injury may be a potential therapeutic target for the treatment of post-traumatic epilepsy.

Long-term injury induced plasticity in {\it Aplysia\/} neurons: Behavioral, electrophysiological, and morphological studies

Nerve injury is known to produce a variety of electrophysiological and morphological neuronal alterations (reviewed by Titmus and Faber, 1990; Bulloch and Ridgeway, 1989; Walters, 1994). Determining if these alterations are adaptive and how they are activated and maintained could provide important insight into basic cellular mechanisms of injury-induced plasticity. Furthermore, characterization of injury-induced plasticity provides a useful assay system for the identification of possible induction signals underlying these neuronal changes. Understanding fundamental mechanisms and underlying induction signals of injury-induced neuronal plasticity could facilitate development of treatment strategies for neural injury and neuropathic pain in humans.^ This dissertation characterizes long-lasting, injury-induced neuronal alterations using the nervous system of Aplysia californica as a model. These changes are examined at the behavioral, electrophysiological, and morphological levels. Injury-induced changes in the electrophysiological properties of neurons were found that increased the signaling effectiveness of the injured neurons. This increase in signalling effectiveness could act to compensate for partial destruction of the injured neuron's peripheral processes. Recovery of a defensive behavioral response which serves to protect the animal from further injury was found within 2 weeks of injury. For the behavioral recovery to occur, new neural pathways must have been formed between the denervated area and the CNS. This was found to be mediated at least in part by new axonal growth which extended from the injured cell back along the original pathway (i.e. into the injured nerve). In addition, injury produced central axonal sprouting into different nerves that do not usually contain the injured neuron's axons. This could be important for (i) finding alternative pathways to the periphery when the original pathways are impassable and (ii) the formation of additional synaptic connections with post-synaptic targets which would further enhance the signalling effectiveness of the injured cell. ^