Gaofeng Wu

Effects of taurine on male reproduction in rats of different ages

BackgroundIt 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.MethodsTaurine and β-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.ResultsThe 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.ConclusionsThe 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.

Antihypertensive Effect of Taurine in Rat

To investigate the effect of taurine on hypertension, a rat model of hypertension was produced by administering N-nitro-L-arginine methylester (L-NAME) to reduce the levels of the vasodilator, nitric oxide. At the same time that L-NAME was administered, taurine treated animals received either 1% or 2% taurine in the drinking water. As a control, 1% taurine was added to the water without L-NAME administration in order to investigate the effects of taurine on blood pressure of normal rats. The results showed that taurine increased serum levels of nitric oxide and nitric oxide synthase, inhibited the elevation of blood pressure, interfered with the activity of the renin-angiotensin-aldosterone system and minimized the elevation in serum cytokine, endothelin, neuropeptide Y and thromboxane B2. It also reduced oxygen derived free radical generation, upregulated the antioxidant defenses and inhibited the proliferation of vascular smooth muscle cells. These data indicate that taurine benefits hypertensive rats, with 2% taurine mediating greater improvement than 1% taurine.

Taurine increases testicular function in aged rats by inhibiting oxidative stress and apoptosis.

In males, the decline of androgen synthesis, spermatogenesis and sexual function are the main phenotypes of aging, which may be attributed to testicular dysfunction. Taurine can act as an antioxidant, a testosterone secretion stimulator, a sperm membrane stabilizer and motility factor, and an anti-apoptotic agent. Recent observational studies suggested that taurine may play an important role in spermatogenesis, but to date whether taurine has anti-aging effects on testes remains unknown. We found that in aged rats testicular SDH and G6PDH activities, marker enzymes of testes, serum testosterone, testicular 3β-HSD and 17β-HSD mRNA expression levels were significantly increased by taurine treatment. Taurine administration also markedly raised the sperm count, viability and motility, decreased the sperm abnormality. Our data suggested that taurine can postpone testicular function deterioration in aged rats. Importantly, we observed obvious elevation of testicular antioxidant enzymes (SOD, GSH, GSH-Px) activities, and remarkable reduction of ROS and MDA by taurine administration, indicating taurine can decrease testicular oxidative stress and lipid peroxidation in aged rats. Finally, we found taurine effectively reduced testicular DNA fragmentation, increased testicular Bcl-2 protein expression, and decreased cytochrome c, Bax, Fas, FasL and caspase-3 expression, suggesting taurine can prohibit aged testicular apoptosis by mitochondrial dependent and independent signal pathway. In summary, our results indicated that taurine can suppress testicular function deterioration by increasing antioxidant ability and inhibiting apoptosis.

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.

Preventive effect of taurine on experimental type II diabetic nephropathy.

BackgroundIt has been verified that taurine has some preventive effects on diabetes and its complications when used alone or together with other drugs, but there are few reports about taurine on the prevention of diabetic nephropathy, the mechanisms of which are still unknown.MethodsTaurine was administered to type II diabetic rats induced by high fat high sugar diet combined with STZ injection. The preventive effect of taurine on diabetic nephropathy was investigated by detecting blood glucose, lipid metabolism, kidney function and glomerular basement membrane metabolism.ResultsTaurine could lower blood glucose, TG, TC, BUN, Scr, NAG, U-PRO, the expression of laminin B1( LBN1) mRNA, and increase HDL-C of diabetic rats.ConclusionsThe results indicated that taurine could prevent the occurrence and development of diabetic nephropathy by decreasing blood glucose, improving lipid metabolism, glomerular basement membrane metabolism, and kidney function.

Effects of Taurine on Myocardial cGMP/cAMP Ratio, Antioxidant Ability, and Ultrastructure in Cardiac Hypertrophy Rats Induced by Isoproterenol

Taurine is the most abundant free amino acid in the human body and accounts for more than 50% of the total amino acid pool in the mammalian heart. To investigate the preventive effects of taurine on cardiac hypertrophy in rats, myocardial injury was established by hypodermic injection of isoprenaline (ISO) (10 mg/kg d) for 7 days. The preventive effects of taurine (100 mg/kg d, 200 mg/kg d, and 300 mg/kg d, i.p) on heart coefficient; ultrastructure of cardiac muscle; the levels of creatine kinase heart isoenzyme (CK-MB), cAMP, and cGMP; and antioxidant ability were investigated. The results showed that taurine could significantly prevent the increase of heart coefficient induced by ISO. Compared with the model group, 100 mg/kg and 200 mg/kg taurine significantly decrease the levels of cAMP and cGMP, while 300 mg/kg taurine could significantly decrease the levels of cAMP in myocardium, and all the three concentrations of taurine could significantly increase the ratio of cGMP/cAMP. The level of serum CK-MB was significantly increased by ISO; 200 mg/kg taurine could significantly decrease it, but 100 mg/kg and 300 mg/kg taurine had no significant effect. As for the antioxidant ability, ISO administration could significantly increase the myocardial level of MDA but had no significant effects on the myocardial levels of SOD, GSH, GSH-Px, and T-AOC. However, taurine administration could significantly decrease the myocardial level of MDA and increase the levels of GSH and T-AOC compared with the model group. The serum levels of SOD, GSH-Px, GSH, and T-AOC were significantly reduced by ISO administration, but the level of MDA showed no significant changes compared with the control group. Taurine administration could significantly increase the serum levels of SOD, GSH-Px, GSH, and T-AOC and decrease the level of MDA compared with the model group. All the results indicated that 200 mg/kg taurine had better effects. The ultrastructure of cardiomyocytes showed that taurine administration could significantly reverse the injury caused by ISO. In conclusion, the present study demonstrated that taurine could inhibit the injury induced by ISO by increasing myocardial negative inotropic effect and antioxidant ability, decreasing the hypertrophic response to isoproterenol and protecting the integrity of -myocardial ultrastructure, decreasing myocardial leak of CK-MB.

Effect of Taurine on Alcoholic Liver Disease in Rats

To investigate the effect of taurine on alcoholic liver disease in rats, male Wistar rats were administered alcohol intragastrically for 3 months. The effect of beta-alanine-mediated taurine depletion and taurine administration on the development of alcoholic liver disease was examined. It was found that taurine administration produced lower levels of aspartate aminotransferase and alkaline aminotransferase than that of the untreated group. In addition, the levels of hepatic total protein, glutathione and superoxide dismutase were higher in the taurine treated groups than in the untreated control or the taurine depleted group, while hepatic malondialdehyde content exhibited the opposite effect. Moreover, the content of hepatic hydroxyproline, serum hyaluronic acid, interleukin-2, interleukin-6, tumor necrosis factor-alpha and laminin were all decreased in the taurine treated group. The pathological changes showed that the percentage of fatty degeneration and inflammation in the taurine group were less than that of the control, taurine depleted and automatic recovery groups. These in-vivo findings demonstrate that hepatic disease caused by chronic alcohol consumption can be prevented and reversed by administration of taurine.

Inhibitory effects of taurine on STZ-induced apoptosis of pancreatic islet cells.

The present research aims to investigate the inhibition effect of taurine on the apoptosis of pancreatic islet cells induced by Streptozotocin (STZ). One hundred male Wistar rats weighing 180-200 g were randomly divided into two groups, rats in the experimental were intraperitoneally injected with 2% STZ (50 mg/kg bw, dissolved in 0.1 mmol/L pH 4.2 citrate buffer), rats in the control group were injected with the same volume of citrate buffer. Rats with the fasting blood glucose level higher than 16.7 mmol/L were selected and randomly divided into four groups: Rats in M group were STZ-induced diabetes rats, rats in T1, T2, and T3 groups were intragastrically administered with taurine (dissolved in 0.5% sodium carboxymethyl cellulose as thickening agent) once a day for 4 weeks with the contents of 0.6 g/kg, 1.2 g/kg, and 2.4 g/kg bw, respectively, while rats in group C and M were given the same amount of thickening agent as T2 group. Four weeks later, pancreatic tissues were fixed and processed for paraffin section. The results showed that STZ induced a significant increase in apoptotic rate of pancreatic islet cells, up-regulated the expression of bax and Fas and down-regulated the expression of Bcl-2, which were significantly blocked by taurine (P < 0.05). The results indicated that taurine could significantly restrain apoptosis of pancreatic islet cells induced by STZ.

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 β-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.

Antidepressant effect of taurine in chronic unpredictable mild stress-induced depressive rats

Depression, a psychiatric and dysthymic disorder, severely affects the learning, work and life quality. The main pathogenesis of depression is associated with central nervous system (CNS) dysfunction. Taurine has been demonstrated to exert protective effects on the brain development and can improve learning ability and memory. Our study investigated the antidepressant-like effects of taurine pre-treatment by examining the changes in depression-like behavior, hormones, neurotransmitters, inflammatory factors and neurotrophic factors in the hippocampus of a chronic unpredictable mild stress (CUMS)-induced depressive rat model. Taurine was found to inhibit the decrease of sucrose consumption and prevent the deficiency of spatial memory and anxiety in rats exposed to CUMS, suggesting a preventive effect of taurine on depression-like behavior. Furthermore, the decreased levels of 5-hydroxytryptamine, dopamine, noradrenaline; the increased levels of glutamate, corticosterone; and the decreased expressions of fibroblast growth factor-2, vascular endothelial growth factor and brain derived neurotrophic factor in depressive rats were hindered by taurine pre-administration. However, tumor necrosis factor-α and interleukin-1β levels were not significantly changed by taurine. The results demonstrated that the anti-depressive effect of taurine may be involved in the regulation of hypothalamic-pituitary-adrenal (HPA) axis and the promotion of neurogenesis, neuronal survival and growth in the hippocampus.