Taurine alleviates high-fat-high-glucose-induced pancreatic islet ß-cell oxidative stress and apoptosis in rat.

The effect of taurine (TAU) as a specific regulatory mediator on pancreatic function in obese rats induced by a high-fat-high-glucose (HFHG) diet was investigated. We fed male Sprague-Dawley rats under different conditions, namely the control, HFHG, TAU, and HFHG + TAU treatment groups for 4 months. Compared with the HFHG group, TAU supplementation significantly reduced malondialdehyde levels and increased superoxide dismutase, total antioxidant capacity, and glutathione levels in the rat pancreas. In addition, TAU significantly decreased the level of reactive oxygen species, and markedly increased the activity of heme oxygenase 1 (HO-1), Kelch-like ECH-associated protein 1 (KEAP-1), and nuclear factor erythrocyte-2-related factor 2 (Nrf2) in the rat pancreas. Notably, HFHG diet could induce pancreatic injury in the rats through the Nrf2/HO-1 signaling pathway and activate the mitochondrial channel-mediated apoptotic signaling pathway. The addition of TAU significantly improved the pancreatic tissue injury induced by the HFHG diet in the rats and reduced the protein expression of Caspase-3, Cleaved-caspase-3, Caspase-9 and Bcl-2 associated protein X (BAX), and increased the protein expression of B-cell lymphoma-2 (Bcl-2). In conclusion, this experiment confirmed that TAU could alleviate the oxidative stress and apoptosis induced by the HFHG diet in rat pancreatic ß-cells.

Effects of Taurine on Serum Indexes of Broilers with Chronic Heat Stress.

The aim of this study was to investigate the effects of taurine on tissue injury, protein metabolism, and basal metabolism of broilers after chronic heat stress by detecting serum physiological and biochemical indices. In the test, 240 AA + broilers at 7 days of age were randomly divided into five groups: the normal temperature control group (24 ± 2 °C) in group C, the heat stress control group (34 ± 2 °C) in HS group, and the LTau, MTau, and HTau groups in heat under stress conditions, 0.5, 2, and 8 g/L taurine were added to the drinking water, and each group was repeated three times. After 2 weeks of feeding at normal temperature, heat stress began. The test period was 4 weeks. Blood was collected at 6 h, 12 h, 7 d, 14 d, 21 d, and 28 d after heat stress, and serum was separated. The results showed that compared with the HS group, the MTau group had significantly higher total serum protein content (P < 0.05), while the other groups were not significantly different (P > 0.05). The MTau and HTau groups had significantly lower serum uric acid levels than the HS group (P < 0.05). At 7d and 14d, the LTau, MTau, and HTau groups all showed significantly increased T3 and T4 concentrations (P < 0.05). There was no significant difference between the groups thereafter (P > 0.05). Compared with HS group, the MTau group contained significantly reduced serum CK activity, LDH activity, AST activity, and ALT activity (P < 0.05). In conclusion, the effects of taurine on tissue damage, protein metabolism, and basal metabolism of broilers after chronic heat stress were studied by measuring serum physiological and biochemical indices. To provide a theoretical basis for the application of taurine in acute heat-stressed broilers.

Antioxidant Effect of Taurine on Chronic Heat-Stressed Broilers.

The purpose of this study was to investigate the effects of taurine on blood indices of broilers with chronic heat stress and to provide theoretical basis for the application of taurine in the anti-chronic heat stress of broilers. In the test, 240 AA + broilers at 7 days of age were randomly divided into five groups: the normal temperature control group (24 ± 2 °C) in group C, the heat stress control group (34 ± 2 °C) in HS group, and the LTau, MTau, and HTau groups in heat under stress conditions, 0.5 g/L, 2 g/L, and 8 g/L taurine, were added to the drinking water, and each group was repeated three times. After 2 weeks of feeding at normal temperature, heat stress began. The test period was 4 weeks. Blood was collected at 6 h, 12 h, 7 d, 14 d, 21 d, and 28 d after heat stress, and serum was separated. The results showed that compared with the HS group, MTau significantly increased the total serum protein content (P < 0.05), but the other groups were not significantly different (P > 0.05). The MTau and HTau groups contained significantly lowered serum uric acid levels than the HS group (P < 0.05). At 7d and 14d, the LTau, MTau, and HTau groups all exhibited significantly increased T3 and T4 concentrations (P < 0.05). There was no significant difference between the groups at other times (P > 0.05). Compared with the HS group, the MTau group contained significantly reduced serum CK activity, LDH activity, AST activity, and ALT activity (P < 0.05). Compared with the LTau, MTau, and HTau groups, serum MDA content was significantly increased in the heat-stressed broilers (P < 0.05). MTau group contained significantly increased T-AOC, SOD, CAT, and GSH-PX levels (P < 0.05). The other groups were not significantly different (P > 0.05). Compared with group C, serum HSP60 and HSP70 levels were significantly elevated in the HS group (P < 0.05). Compared with the HS group, the LTau and MTau groups contained significantly increased serum HSP60 and HSP70 concentrations (P < 0.05), but the other groups were not significantly different (P > 0.05). In conclusion, taurine can alleviate the symptoms of chronic heat stress of broilers, regulate the metabolism of the body, and improve the antioxidant activity of the body.

CPT1A-mediated fatty acid oxidation promotes cell proliferation via nucleoside metabolism in nasopharyngeal carcinoma.

As the first rate-limiting enzyme in fatty acid oxidation (FAO), CPT1 plays a significant role in metabolic adaptation in cancer pathogenesis. FAO provides an alternative energy supply for cancer cells and is required for cancer cell survival. Given the high proliferation rate of cancer cells, nucleotide synthesis gains prominence in rapidly proliferating cells. In the present study, we found that CPT1A is a determining factor for the abnormal activation of FAO in nasopharyngeal carcinoma (NPC) cells. CPT1A is highly expressed in NPC cells and biopsies. CPT1A dramatically affects the malignant phenotypes in NPC, including proliferation, anchorage-independent growth, and tumor formation ability in nude mice. Moreover, an increased level of CPT1A promotes core metabolic pathways to generate ATP, inducing equivalents and the main precursors for nucleotide biosynthesis. Knockdown of CPT1A markedly lowers the fraction of 13C-palmitate-derived carbons into pyrimidine. Periodic activation of CPT1A increases the content of nucleoside metabolic intermediates promoting cell cycle progression in NPC cells. Targeting CPT1A-mediated FAO hinders the cell cycle G1/S transition. Our work verified that CPT1A links FAO to cell cycle progression in NPC cellular proliferation, which supplements additional experimental evidence for developing a therapeutic mechanism based on manipulating lipid metabolism.

Taurine Increases Spermatozoa Quality and Function in Asthenospermia Rats Impaired by Ornidazole.

Asthenospermia has been considered as one of the crucial causes of male infertility, which was closely related to epididymal dysfunction. Lots of documents have revealed that taurine palys an important role in male reproduction, including antioxidation, membrane stabilization, stimulation of sexual hormone secretion and elevation of sperm quality. The objective of this study was to expose the effect of taurine on spermatozoa quality and function in ornidazole-induced asthenospermia rats. We found that taurine treatment could obviously recover the decline of cauda epididymal sperm count, viability and motility, and the elevation of sperm abnormality in asthenospermia animals. Spermatozoa acrosin, LDH-X, SDH and CCO activities of model rats also were notably increased by taurine administration. The present data indicated that taurine could raise spermatozoa quality and function by elevating mitochondrial energy metabolism. Notably, taurine supplementation markedly raised serum GnRH, LH and T levels in asthenospermia rays, suggesting taurine rescued asthenosperm by means of stimulating hypothalamic-pituitary-testicular axis secretion. We also found that concentrations of asthenospermia epididymal carnitine, SA, α-Glu and ACP, and mRNA expression levels of MMP7 and IDO2 were significantly rised by taurine administration, indicating taurine may protect epididymal epithelium structure, improve secretion activity, and maintain intraluminal microenvironment homeostasis. Finally, the present results showed taurine effectively increased cauda epididymal SOD, GSH and γ-GT levels in model rats, reduced ROS and MDA production, suggesting epididymal antioxidant ability of asthenospermia rats could be elevated by taurine treatment. To sum up, our results indicated that taurine can promote spermatozoa quality and function in ornidazole-induced asthenospermia rats by facilitating epididymal epithelium secretion and luminal microenvironment homeostasis.

Phased uplift of the northeastern Tibetan Plateau inferred from a pollen record from Yinchuan Basin, northwestern China.

The uplift of the Tibetan Plateau (TP) significantly affected both regional and global climates. Although there is evidence that the Tibetan Plateau experienced uplift during the Quaternary, the timing and amplitude are poorly constrained. However, the increased availability of long sedimentary records of vegetation change provides an opportunity to reconstruct the timing of the uplift. Here, we present a well-dated, high-resolution pollen record for the last 2.6 Ma from the Yinchuan Basin, which was incised by the Yellow River with its source in the northeastern Tibetan Plateau. Variations in the Artemisia/Chenopodiaceae (A/C) ratio of the reveal changes in moisture conditions in the Yinchuan Basin during glacial-interglacial cycles, as well as a gradual long-term aridification trend which is consistent with progressive global cooling. However, fluctuations in the percentages of Picea and Abies differ from those of the A/C ratio and we propose that they reflect changes in the vegetation and environment of high elevation areas. The Picea and Abies records reveal two phases of increased representation, at 2.1 and 1.2 Ma, which may indicate phases in the uplift of the northeastern Tibetan Plateau. Thus, they provide independent evidence for the timing of the uplift of the Tibetan Plateau during the Quaternary.

Taurine Improves Sexual Function in Streptozotocin-Induced Diabetic Rats.

Previous studies have identified that diabetic erectile dysfunction is associated with androgen and nitric oxide deficiency resulting from hyperglycemia. It has been demonstrated that taurine can stimulate testosterone secretion, increase nitric oxide synthase (NOS) activity and nitric oxide (NO) production, and reduce blood glucose levels in the diabetic animals. Furthermore, recent studies have found that taurine relaxes both the corpus cavernosum and the vasculature. Accordingly, we hypothesized that taurine might exert beneficial effects on erectile function of the diabetic rats. Here, we assessed the effects of taurine on sexual function in streptozotocin (STZ) -induced diabetic male rats. We observed that taurine treatment could markedly increase sexual response and mating ability of STZ-diabetic rats. The serum concentration of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone (T) were also significantly increased by taurine administration. Importantly, taurine supplementation notably increased mRNA levels and activity of endothelial NOS (eNOS) and neuronal NOS (nNOS), as well as NO and cGMP content, in the corpus cavernosum of the diabetic rats. In conclusion, the present data indicate that taurine can increase sexual function of STZ-induced diabetic male rats mainly by correcting the diabetes, increasing sexual desire, which is implicated in ameliorating the hypothalamic-pituitary-testicular axis function, and by improving penile erection, which requires increased signaling from the penile endothelial- and neuronal-dependent NO-cGMP pathway.

Taurine Increases Insulin Expression in STZ-Treated Rat Islet Cells In Vitro.

This research aims at figure out the effects and the pathway of taurine on insulin in islet cells cultured in vitro treated by STZ. In the experiment, islet cells were isolated from pancreatic tissue by in situ perfusion with collagenase V. The pancreatic islet cells, maintained in RPMI 1640 culture medium were divided into six groups: C: control, E: supplemented with 10 mmol/L of taurine, group M, T1, T2 and T3 was treated with STZ (0.5 mmol/L), at the same time, taurine were added in group T1,T2 and T3 for 30 min, and then culture medium were collected by centrifugation and then insulin levels were detected by radioimmunoassay, the cells were then rinsed with Hanks, and 0,10, 0, 5, 10, 20 mmol/L of taurine in group C, E, M, T1, T2 and T3 were added for 24 h respectively. Total RNA was extracted, then insulin gene and its transcription regulator such as PDX-1, NeuroD1 were amplified by semi-quantitative RT-PCR. The results showed that, the release of insulin from islet cells treated by STZ could be inhibited by taurine, gene expression of insulin, PDX-1 and NeuroD1 in STZ group decreased significantly, which were up-regulated by taurine administration. In conclusion, taurine exerts a certain degree of protective and reconstructive effects on islet cells treated by STZ.

Taurine Recovers Testicular Steroidogenesis and Spermatogenesis in Streptozotocin-Induced Diabetic Rats.

A great deal of investigations have verified that diabetic male reproductive impairment is associated with the dysfunction of testicular steroidogenesis and spermatogenesis resulted from insulin deficiency and hyperglycaemia-induced oxidative stress. It has been identified taurine is profitable for diabetes mellitus and diabetic implications through its insulin-like and islet cells protective activity. Furthermore, our previous studies found that taurine could increase testicular antioxidative ability, stimulate the endocrine activity of hypothalamic-pituitary-testicular axis, elevate testosterone level, raise sperm quality, suppress the deterioration of testicular function. Accordingly, we hypothesized that taurine may have beneficial effects on testicular dysfunction under diabetic mellitus status. Here, we investigated the effects of taurine on testicular steroidogenesis and spermatogenesis in streptozotocin (STZ)-induced type I diabetic rats. We observed that taurine treatment can markedly increase the body and testis weights, testicular SDH and G6PDH activities, decrease the serum fasting glucose concentration of diabetic rats. Serum contents of GnRH, LH, FSH, T, and testicular StAR, 3ß-HSD, 17ß-HSD mRNA expression levels were also obviously raised by taurine administration, indicating that taurine can improve testicular steroidogenesis in diabetic animals. Finally, we found taurine supplementation effectively elevated the sperm count and motility, reduced sperm abnormality, suggesting that taurine can increase the testicular spermatogenesis function of diabetic rat. In summary, the present data indicated that taurine can rescue the function of testicular steroidogenesis and spermatogenesis in STZ-induced type I diabetic rats possibly by increasing the endocrine activity of hypothalamic-pituitary-testicular axis.

Effects of Replacement of Methionine in Diets with Taurine on Growth Performance and Blood Index in Broilers.

We studied effects of replacement of methionine with taurine on growth performance and blood index of AA+ broilers. Six hundred 1 day broilers were divided into 5 groups, with 3 replicates of 40 broilers in each. The experiment lasted for 42 days.The control group were fed on formulated diets containing 2% methionine; the other groups were offered feed with equal nitrogen and calories to the control group, but contained 25, 50, 75 and 100% taurine in place of methionine.Compared with the control group, no significant differences were observed in growth performance of 1-21 days broilers, or the serum LDL-C, TC, IgG and SOD of the experimental groups (P> 0.05). ADG and F/G from days 1-42, ADG, ADFI and F/G from days 22-42 were significantly different between the experimental groups and the control group (P < 0.05). ADFI and Mortality in 50, 75 and 100% taurine groups were significantly different compared with the control group (P < 0.05). IgM and GSH-PX of 50 and 75% taurine groups were significantly different compared with the control group (P < 0.05). Serum HDL-C, T-AOC levels in 50, 75 and 100% taurine groups were significantly different compared with the control group (P < 0.05). Based on the quadratic regression analysis, the best replacement ratios were 58%, 61% and 61% on days 1-21, 22-42, and 1-42, respectively. In conclusion, appropriate levels of taurine supplement can improve growth performance, immune system, T-AOC, and lipid metabolism.

Differential expression profiling of hypothalamus genes in laying period and ceased period Huoyan geese.

The hypothalamus plays a central role in controlling poultry reproductive activity. To increase our understanding of genes involved in egg laying of Huoyan geese, gene profiles in the hypothalamus of laying period and ceased period Huoyan geese were investigated using suppression subtractive hybridization (SSH) method. A total of 95 differentially expressed sequence tags (ESTs), including 46 up-regulated and 49 down-regulated sequences showed homology to known genes of the non-redundant NCBI databases. Bioinformatic analysis demonstrated that these genes were mainly involved in anatomical structure development, signal transduction, cellular nitrogen compound metabolic process, biosynthetic process, cellular protein modification process, cell differentiation, transport, cell adhesion, and reproduction. Ten ESTs were selected for further analyses by quantitative real-time RT-PCR (qRT-PCR). Whose most part of results were consistent with the SSH results. Of note, AdipoR2, Nrg1, and NCAM1, which related with secretion of GnRH and other hormones, were identified to be differentially expressed between laying period and ceased period. These findings provided a new source for mining genes related to higher laying performance of Huoyan geese, which facilitate our understanding of the reproductive biology of the goose.

Taurine enhances the sexual response and mating ability in aged male rats.

It has been demonstrated that taurine is abundant in male reproductive organs, and can be biosynthesized by testis, but the taurine concentration will reduce with aging. The levels of serum LH, T, NOS, and NO were found to be obviously increased by taurine supplementation in aged rats in our previous study. In addition, aging will result in a significant decline in sexual response and function, which may be attributed to the androgen deficiency. Furthermore, NO has been proposed as a crucial mediator of penile erection. That makes us hypothesize that there is potential relationship between taurine decline and erection dysfunction in aged males. So the primary aim of the present study was to investigate the effect of taurine on male sexuality in rats. Taurine was offered in water to male aged (20 months old) rats for 110 days. The effects of taurine on the sexual response, mating ability, levels of serum reproductive hormones, and penile NOS and NO levels were investigated. The results showed that taurine can significantly reduce the EL and ML; obviously increase the ERF, MF, IF, and EJF; stimulate the secretion of GnRH, LH, and T; and elevate penis NOS and NO level in aged rats. The results indicated that taurine can enhance the sexual response and mating ability in aged male rats by increasing the level of testosterone and NO, but the exact mechanism of which needs to be further investigated.

Taurine counteracts the suppressive effect of lipopolysaccharide on neurogenesis in the hippocampus of rats.

Neurogenesis has been generally accepted to happen in the subventricular zone lining the lateral ventricular and subgranular zone (SGZ) in the hippocampus of adult mammalian brain. Recent studies have reported that inflammatory stimuli, such as injection of lipopolysaccharide (LPS), impair neurogenesis in the SGZ. Taurine, a sulfur-containing ß-amino acid, is a major free intracellular amino acid in many tissues of mammals and having various supplementary effects on the mammalian body functions including the brain. Recently, it has been also reported that taurine levels in the brain significantly increase under stressful conditions. The present study was aimed to evaluate the possible beneficial effects of taurine on the neurogenesis in the SGZ under the condition of acute inflammatory stimuli by LPS. Adult male rats were intraperitoneally injected with taurine once a day for 39 days. Twenty-four hours before the animals were sacrificed on the last day of taurine treatment, LPS was injected simultaneously with bromodeoxyuridine (BrdU). Immunohistochemistry for BrdU, Ki67, and Iba-1 in the brain was performed, and serum levels of TNF-α and IL-1ß 2 h after LPS injection were determined. The results showed that LPS significantly decreased the number of immunoreactive cells for both BrdU and Ki67 in the SGZ, while increased that for Iba-1, all of which were restored by taurine administration. Meanwhile, the serum concentrations of TNF-α and IL-1ß were significantly increased, which were significantly attenuated by taurine administration. These results suggest that taurine effectively maintains neurogenesis in the SGZ under the acute infectious condition by attenuating the increase of microgliosis in the hippocampus as well as proinflammatory cytokines in the peripheral circulation.

Taurine and Chinese traditional medicine accelerate alcohol metabolism in mice.

Excessive alcohol consumption is dangerous and causes serious damage to health. The main organ capable of alcohol oxidizing is liver which is also the main organ synthesizing taurine, a sulfur-containing ß-amino acid, which is the major free intracellular amino acid presenting in many tissues of human and animals and exerting many physiologic and pharmacologic functions. To investigate the effect of taurine and Chinese traditional medicine on alcohol metabolism after acute alcoholic intake, male Kunming mice were administered with 60% alcohol (0.4 ml) intragastrically. Water, taurine, or taurine coadministration with Chinese traditional medicine was intragastrically administered to mice 30 min before or after alcohol intake. The disappearance of body-righting reflex was used to determine the intoxication of mice. Durations between alcohol intake and intoxication (tolerance time), intoxication and recovery (maintenance time) were recorded. The concentration of blood alcohol, levels of hepatic alcohol dehydrogenase (ADH), and acetaldehyde dehydrogenase (ALDH) were detected at 20, 50, 90, 120, and 150 min after alcohol intake. The results showed that taurine administered alone or together with Chinese traditional medicine could both significantly reduce the number of intoxicated mice, postpone the tolerance time, shorten the maintenance time, and could obvisouly decrease blood level of alcohol, increase hepatic levels of ADH and ALDH. The results indicated that taurine administered alone or together with traditional Chinese medicine could significantly accelerate the metabolism of alcohol, reduce the toxicity of alcohol, and coadministration of taurine and traditional Chinese medicine had better effects.

Effects of taurine on male reproduction in rats of different ages.

BACKGROUND: It has been demonstrated that taurine is one of the most abundant free amino acids in the male reproductive system, and can be biosynthesized by male reproductive organs. But the effect of taurine on male reproduction is poorly understood. METHODS: Taurine and beta-alanine (taurine transport inhibitor) were offered in water to male rats of different ages. The effects of taurine on reproductive hormones, testis marker enzymes, antioxidative ability and sperm quality were investigated. RESULTS: The levels of T and LH were obviously increased by taurine supplementation in rats of different ages, and the level of E was also significantly elevated in baby rats. The levels of SOD, ACP, SDH and NOS were obviously increased by taurine administration in adult rats, but the levels of AKP, AST, ALT and NO were significantly decreased. The levels of SOD, ACP, LDH, SDH, NOS, NO and GSH were significantly elevated by taurine administration in aged rats, but the levels of AST and ALT were significantly decreased. The motility of spermatozoa was obviously increased by taurine supplement in adult rats. The numbers and motility of spermatozoa, the rate of live spermatozoa were significantly increased by taurine supplement in aged rats. CONCLUSIONS: The present study demonstrated that a taurine supplement could stimulate the secretion of LH and T, increase the levels of testicular marker enzymes, elevate testicular antioxidation and improve sperm quality. The results imply that taurine plays important roles in male reproduction especially in aged animals.

[Vasorelaxational effects of procyanidins on rabbit aorta in vitro and decreasing arterial blood pressure in vivo].

OBJECTIVE: To study the vasodilation effect of the procyanidin (PC) extracted from grape seeds on rabbit thoracic aortic rings in vitro, decreasing blood pressure in vivo and the possible mechanism. METHOD: Rabbits aortic rings were isolated and were divided into six groups including removal of endothelium, integrity of endothelium, 1 x 10(-5) mol X L(-1) indomethacin (Indo), 1 x 10(-5) mol x L(-1) propranolol (Prop), 1 x 10(-4) mol x L(-1) N(omega)-nitro-L-arginine (L-NNA) and 1 x 10(-5) mol x L(-1) methylene blue (MB). Then the thoracic aortic rings were treated with PC with cumulative concentrations of 1.25, 2.5, 5.0 mg x L(-1) respectively and the changes of tension were recorded, and investigate the effect of 40 mg x L(-1) PC on the contraction of aortic smooth muscles, thoracic aortic rings were pre-treated with NA (1 x 10(-8) to approximately 1 x 10(-5) mol x L(-1)), KCl (6.3 to approximately 100 mmol x L(-1)) and CaCl2 (1 x 10(-5) to approximately 1 x 10(-5) mol x L(-1)) followed by treatment with PC. Then, rabbits common carotid artery was intubated and arterial blood pressure in vivo was recorded. PC with cumulative concentrations of 4.0, 8.0, 16, 32, 64, 84 mg x kg(-1) was injected into vein and the changes of arterial blood pressure were observed. RESULT: PC could relax isolated rabbit aorta and showedan obvious concentration-dependent relaxation (r = 0. 63, P < 0.001). The relaxant effect of PC was significantly reduced by removal of endothelium and by treatment with nitric oxide synthase inhibitor L-NNA, or guanylyl cyclase inhibitor MB. In addition PC could decrease the dose response curves of aortic rings to NA, KCl and CaCl2. PC has a significant concentration-dependent negative effect on arterial blood pressure in vivo (r = 0.92, P < 0.001). CONCLUSION: PC has a vasodilation effect not only in an endothelium-dependent, nitric oxide involved manner, but in inhibition of calcium release and blockage of potential-dependent calcium channels. PC could decrease the rabbit's arterial blood pressure significantly in vivo.