The effect of taurine on polymorphonuclear leukocyte functions in endotoxemia

Chronic Methylmercury Intoxication Induces Systemic Inflammation, Behavioral, and Hippocampal Amino Acid Changes in C57BL6J Adult Mice

Methylmercury (MeHg) is highly toxic to the human brain. Although much is known about MeHg neurotoxic effects, less is known about how chronic MeHg affects hippocampal amino acids and other neurochemical markers in adult mice. In this study, we evaluated the MeHg effects on systemic lipids and inflammation, hippocampal oxidative stress, amino acid levels, neuroinflammation, and behavior in adult male mice. Challenged mice received MeHg in drinking water (2 mg/L) for 30 days. We assessed weight gain, total plasma cholesterol (TC), triglycerides (TG), endotoxin, and TNF levels. Hippocampal myeloperoxidase (MPO), malondialdehyde (MDA), acetylcholinesterase (AChE), amino acid levels, and cytokine transcripts were evaluated. Mice underwent open field, object recognition, Y, and Barnes maze tests. MeHg-intoxicated mice had higher weight gain and increased the TG and TC plasma levels. Elevated circulating TNF and LPS confirmed systemic inflammation. Higher levels of MPO and MDA and a reduction in IL-4 transcripts were found in the hippocampus. MeHg-intoxication led to increased GABA and glycine, reduced hippocampal taurine levels, delayed acquisition in the Barnes maze, and poor locomotor activity. No significant changes were found in AChE activity and object recognition. Altogether, our findings highlight chronic MeHg-induced effects that may have long-term mental health consequences in prolonged exposed human populations.

Methyl donor supply to heat stress-challenged polymorphonuclear leukocytes from lactating Holstein cows enhances 1-carbon metabolism, immune response, and cytoprotective gene network abundance

Mechanisms controlling immune function of dairy cows are dysregulated during heat stress (HS). Methyl donor supply-methionine (Met) and choline (Chol)-positively modulates innate immune function, particularly antioxidant systems of polymorphonuclear leukocytes (PMN). The objective of this study was to investigate the effect of Met and Chol supply in vitro on mRNA abundance of genes related to 1-carbon metabolism, inflammation, and immune function in short-term cultures of PMN isolated from mid-lactating Holstein cows in response to heat challenge. Blood PMN were isolated from 5 Holstein cows (153 ± 5 d postpartum, 34.63 ± 2.73 kg/d of milk production; mean ± SD). The PMN were incubated for 2 h at thermal-neutral (37°C; TN) or heat stress (42°C; HS) temperatures with 3 levels of Chol (0, 400, or 800 μg/mL) or 3 ratios of Lys:Met (Met; 3.6:1, 2.9:1, or 2.4:1). Supernatant concentrations of IL-1β, IL-6, and tumor necrosis factor-α were measured via bovine-specific ELISA. Fold-changes in mRNA abundance were calculated separately for Chol and Met treatments to obtain the fold-change response at 42°C (HS) relative to 37°C (TN). Data were subjected to ANOVA using PROC MIXED in SAS (SAS Institute Inc., Cary, NC). Orthogonal contrasts were used to determine the linear or quadratic effect of Met and Chol for mRNA fold-change and supernatant cytokine concentrations. Compared with PMN receiving 0 μg of Chol/mL, heat-stressed PMN supplemented with Chol at 400 or 800 μg/mL had greater fold-change in abundance of CBS, CSAD, GSS, GSR, and GPX1. Among genes associated with inflammation and immune function, fold-change in abundance of TLR2, TLR4, IRAK1, IL1B, and IL10 increased with 400 and 800 μg of Chol/mL compared with PMN receiving 0 μg of Chol/mL. Fold-change in abundance of SAHH decreased linearly at increasing levels of Met supply. A linear effect was detected for MPO, NFKB1, and SOD1 due to greater fold-change in abundance when Met was increased to reach Lys:Met ratios of 2.9:1 and 2.4:1. Although increasing Chol supply upregulated BAX, BCL2, and HSP70, increased Met supply only upregulated BAX. Under HS conditions, enhancing PMN supply of Chol to 400 μg/mL effectively increased fold-change in abundance of genes involved in antioxidant production (conferring cellular processes protection from free radicals and reactive oxygen species), inflammatory signaling, and innate immunity. Although similar outcomes were obtained with Met supply at Lys:Met ratios of 2.9:1 and 2.4:1, the response was less pronounced. Both Chol and Met supply enhanced the cytoprotective characteristics of PMN through upregulation of heat shock proteins. Overall, the modulatory effects detected in the present experiment highlight an opportunity to use Met and particularly Chol supplementation during thermal stress.

Taurine alleviates lipopolysaccharide‑induced liver injury by anti‑inflammation and antioxidants in rats

The aim of the present study was to investigate the protective effect of taurine on lipopolysaccharide (LPS)-induced liver injury and its mechanisms. Male rats were randomly divided into three groups: Normal saline, LPS model and taurine treatment. Experimental animals were treated with saline or taurine (dissolved in saline, 200 mg/kg/day) via intravenous injection. After 2 h, saline or LPS (0.5 mg/kg) was administrated via intraperitoneal injection. Markers of liver injury, pro-inflammatory cytokines and superoxide dismutase (SOD) activity were determined in plasma. Liver tissues were removed for morphological analysis and determination by western blot analysis. Taurine significantly reduced the elevation in the levels of LPS-induced aspartate transaminase and alanine transaminase and decreased the concentrations of LPS-induced inflammatory factors including tumor necrosis factor-α and interleukin-6. Taurine also increased the activity of SOD in serum and the expression of heme oxygenase-1 protein in liver tissue. Taurine pretreatment also reduced the elevated expression levels of LPS-induced cyclooxygenase-2, nuclear factor κB and extracellular regulated protein kinase. The results from the present study demonstrated that taurine alleviates LPS-induced liver injury. The beneficial role of taurine may be associated with its reduction of pro-inflammatory response and oxidative stress.

Protective effect of genistein isolated from Hydrocotyle sibthorpioides on hepatic injury and fibrosis induced by chronic alcohol in rats

This study examined the effect of genistein isolated from Hydrocotyle sibthorpioides on chronic alcohol-induced hepatic injury and fibrosis. Rats underwent intragastric administration of alcohol (5.0-9.5g/kg) once a day for 24 weeks. A subset of rats were also intragastrically treated with genistein (0.5, 1 or 2mg/kg) once a day. Genistein significantly decreased the plasma alcohol concentration, inhibited the activities of alanine and aspartate aminotransferases and decreased levels of inflammatory mediators, including interleukin 6, tumor necrosis factor-α and myeloperoxidase, via down-regulation of nuclear factor-κB. Moreover, genistein effectively inhibited collagen deposition and reduced pathological tissue damage as determined by hepatic fibrosis biomarkers, such as total hyaluronic acid, laminin, and type III collagen. Mechanistically, studies showed that genistein markedly reduced lipid peroxidation, recruited the anti-oxidative defense system, inhibited CYP2El activity, promoted extracellular matrix degradation by modulating the levels of tissue inhibitor of matrix metalloproteinase-1 and matrix metalloproteinase-2, induced HSC apoptosis by down-regulating B-cell lymphoma 2 mRNA, and inhibited the expression of α-smooth muscle actin and transforming growth factor β(1) proteins. In conclusion, genistein exerts a preventative effect to ameliorate developing liver injury and even liver fibrosis induced by chronic alcohol administration in rats.

Protective effect of Fufang-Liu-Yue-Qing, a traditional Chinese herbal formula, on CCl4 induced liver fibrosis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese prescription Fufang-Liu-Yue-Qing (FLYQ) has long been employed clinically to treat chronic hepatitis B, and we have reported its beneficial effects on liver fibrosis in vitro. The present study was investigated to verify protective effects of FLYQ on liver fibrosis in a rat model and to investigate the underlying mechanisms which have not been explored yet.

MATERIALS AND METHODS

Liver fibrosis was established by intragastric administration of 2 ml/kg CCl(4) twice a week for 12 weeks. During the experiment, the model group received CCl(4) only, and the normal control group received an equal volume of saline. Treatment groups received not only CCl(4) for 12 weeks, but also the corresponding drugs, colchicine (1.00 mg/kg/day) or FLYQ (300, 150, 75 mg/kg/day) from 5 to 12 weeks.

RESULTS

Analysis experiments showed that FLYQ could significantly alleviate liver injury, as indicated by decreasing levels of ALT, AST, ALP, GGT, IL-6 and TNF-α. Moreover, FLYQ could effectively inhibit collagen deposition and reduce the pathological tissue damage. Research on mechanism showed that FLYQ was able to markedly reduce lipid peroxidation, recruit the anti-oxidative defense system, promote ECM degradation by modulating the levels of TIMP-1 and MMP-2, and induce HSC apoptosis by down-regulating bcl-2 mRNA, as well as inhibit the expressions of α-SMA and TGF-β(1) proteins.

CONCLUSIONS

Our results show that FLYQ is effective in attenuating hepatic injury and fibrosis in the CCl(4)-induced rat model, which should be developed as a new drug for treatment of liver fibrosis and even cirrhosis.

Effects of a 900-MHz electromagnetic field on oxidative stress parameters in rat lymphoid organs, polymorphonuclear leukocytes and plasma

BACKGROUND AND AIMS

The present study investigated the effects of a 900-MHz electromagnetic field (EMF) for 2 h/day for 45 days on lymphoid organs (spleen, thymus, bone marrow), polymorphonuclear leukocytes (PMNs) and plasma of rats, focusing on changes in the enzymatic and nonenzymatic antioxidant system. We determined whether there is any difference between immature and mature rats in terms of oxidative damage caused by EMF and tested recovery groups to determine whether EMF-induced damage is reversible in immature and mature rats.

METHODS

Twenty four immature and 24 mature rats were divided randomly and equally into six groups as follows: two control groups, immature (2 weeks old) and mature (10 weeks old); two groups were exposed to 900 MHz (28.2 ± 2.1 V/m) EMF for 2 h/day for 45 days. Two recovery groups were kept for 15 days after EMF exposure.

RESULTS

Substantial, deleterious biochemical changes were observed in oxidative stress metabolism after EMF exposure. Antioxidant enzyme activity, glutathione levels in lymphoid organs and the antioxidant capacity of the plasma decreased, but lipid peroxidation and nitric oxide levels in PMNs and plasma and also myeloperoxidase activity in PMNs increased. Oxidative damage was tissue specific and improvements seen after the recovery period were limited, especially in immature rats.

CONCLUSIONS

In the present study, much higher levels of irreversible oxidative damage were observed in the major lymphoid organs of immature rats than in mature rats.

Regression of liver fibrosis by taurine in rats fed alcohol: effects on collagen accumulation, selected cytokines and stellate cell activation

The antifibrogenic effect of taurine in experimental liver fibrosis has been shown. The role of taurine to abate fibrogenic mediators and collagen deposition during liver fibrosis induced by simultaneous administration of iron carbonyl (0.5% w/w) and alcohol (6 g/kg/day) was investigated in this study. Liver histology, the levels of inflammatory cytokines, stellate cell activation, oxidative stress and collagen content were assessed. Liver fibrosis and a rise in collagen content in ethanol plus iron-fed rat were evident from van Gieson and Masson's trichrome staining respectively. Hepatic myeloperoxidase activity and plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were markedly elevated. This was associated with an imbalance in the oxidant-antioxidant system, increased expression of transforming growth factor-β(1) (TGF-β(1)) and stellate cell activation suggested by α-smooth muscle actin (α-SMA) localization. This condition was protected in the presence of taurine. Taurine lowered the levels of IL-6, TNF-α and peroxidation products and the expression of α-SMA, desmin and TGF-β(1) and improved the antioxidant status. A positive relationship between hepatic collagen with iron and lipid peroxides and an inverse relationship between collagen and glutathione were noted. It is concluded that taurine reduces iron-potentiated alcoholic liver fibrosis by curtailing oxidative stress, production of inflammatory and fibrogenic mediators and activation of stellate cells.

Inhibitory effects of taurine and oat fiber on intestinal endotoxin release in rats

Numerous studies have demonstrated that endotoxin plays an important role in the development and progression of hepatic cirrhosis. However, there is no effective remedy for the prevention and treatment of intestinal endotoxemia. Taurine has been reported to have beneficial effects on endotoxemia. Oats have been shown to absorb intestinal toxins and increase excretion of intestinal toxins. The present study was to investigate whether a combination of taurine and oat has an additive inhibitory effect on endotoxin release in a rat liver ischemia/reperfusion model. Our results showed that the combination of taurine (300mgkg(-1)d(-1)) and oat fiber (15gkg(-1)d(-1)) significantly reduced endotoxin levels in the portal vein by 36.3% when compared to the control group (0.168+/-0.035Eu/ml in the treatment group vs 0.264+/-0.058Eu/ml in the control group, P<0.01). The treatment of taurine (300mgkg(-1)d(-1)) and oat fiber (15gkg(-1)d(-1)) induced 21.5% and 18.4% reduction in endotoxin levels, respectively, when compared to the control group (P<0.05). We conclude that the combination of taurine and oat fiber achieved an additive inhibitory effect on intestinal endotoxin release, which might be an effective approach for the treatment of intestinal endotoxemia.

Attenuating effect of taurine on lipopolysaccharide-induced acute lung injury in hamsters

This study has evaluated the ability of the semiessential amino acid taurine to attenuate lipopolysaccharide (LPS)-induced lung inflammation, oxidative stress and apoptosis in a small animal model. For this purpose, bacterial LPS (0.02mg in phosphate buffered saline (PBS) pH 7.4) was instilled intratracheally into female Golden Syrian hamsters, before or after a 3-day intraperitoneal treatment with a single dose (50mg/kg in PBS pH 7.4) of taurine. At 24h after the last treatment, lung tissue and bronchoalveolar lavage fluid (BALF) samples were collected. In comparison to samples from animals receiving only PBS pH 7.4, serving as controls, those of LPS-stimulated animals exhibited a higher count of both total leukocytes and neutrophils in the BALF, and increased incidence of apoptosis, depletion of intracellular glutathione and evidence of inflammation confined to the parenchyma in the lung. In addition, LPS caused cells in the BALF to exhibit a higher expression of tumor necrosis factor-1, a higher activity of caspase-3, marked lipid peroxidation, and altered activities of catalase, glutathione peroxidase and superoxide dismutase relative to control samples. In contrast, a treatment with taurine was found to significantly attenuate all of the cellular and biochemical alterations induced by LPS, more so when given before rather than after the endotoxin. The present results suggest that taurine possesses intrinsic antiinflammatory and antioxidant properties that may be of benefit against the deleterious actions of LPS in the lung.