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Studies have shown that CSD mRNA and protein are expressed in vas deferens, epididymis and testis, especially in Leydig cells of testis ( 10). Cysteine sulfinate decarboxylase (CSD) is a key enzyme in taurine biosynthesis pathway ( 9). Taurine has been proved to be biosynthesized in the reproductive system of male animals. Therefore, taurine treatment is beneficial to various pathologies. In addition, dietary taurine deficiency in species with low taurine biosynthesis rate (such as cats and foxes) can lead to many diseases, such as retinal degeneration ( 5), dilated cardiomyopathy ( 6), immune dysfunction ( 7) and reproductive defects ( 8). On the other hand, dietary taurine is mainly obtained from meat, seafood, or energy drinks ( 3, 4). Taurine is mainly synthesized by methionine and cysteine in liver, and its synthesis ability is limited ( 2). The sources of taurine in the body are biosynthesis and dietary intake. Although taurine is not involved in the synthesis and metabolism of protein, as a functional component, it is involved in a variety of physiological functions, including bile formation in the liver, modulation of calcium flow, osmoregulation, neurotransmitter or neuromodulator, antiarrhythmic activity, etc. Taurine is a sulfur-containing nonprotein amino acid that has been found to be one of the most abundant amino acids in mammalian plasma and tissues. Therefore, this article reviewed the protective effect of taurine on male reproductive function and its detailed mechanism, in order to provide reference for further research and clinical application. Related mechanisms include reduced oxidative stress, increased antioxidant capacity, inhibited inflammation and apoptosis, restored the secretory activity of the HPT axis, reduced chromosomal variation, enhanced sperm mitochondrial energy metabolism, cell membrane stabilization effect, etc. In addition, taurine acts as a protective agent against toxic damage to the male reproductive system by exogenous substances (e.g., therapeutic drugs, environmental pollutants, radiation). In pathology, taurine supplement may be beneficial to alleviate pathological damage of male reproductive system, including oxidative damage of sperm preservation in vitro, testicular reperfusion injury and diabetes -induced reproductive complications. In physiology, taurine can promote the endocrine function of the hypothalamus-pituitary-testis (HPT) axis, testicular tissue development, spermatogenesis and maturation, delay the aging of testicular structure and function, maintain the homeostasis of the testicular environment, and enhance sexual ability. Recently, accumulating data showed that taurine has a potential protective effect on reproductive function of male animals. Taurine has been proved to be synthesized and abundant in male reproductive organs. Taurine, a sulfur-containing amino acid, has a wide range of biological effects, such as bile salt formation, osmotic regulation, oxidative stress inhibition, immunomodulation and neuromodulation. 3School of Basic Medical Science, Henan University, Henan, Kaifeng, China.2Arts Department, School of Kaifeng Culture and Tourism, Henan, Kaifeng, China.1Institute of Nursing and Health, School of Nursing and Health, Henan University, Kaifeng, Henan, China.Yuanyuan Li 1† Qianwen Peng 1† Jia Shang 2 Wanglin Dong 1 Sijia Wu 1 Xiajun Guo 1 Zhenxing Xie 3* Chaoran Chen 1*
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