This study aimed to evaluate the effect of N-acetyl cysteine on the male reproductive system and consensus and classification of data found from previous studies. It is undeniable that N-acetyl cysteine as a powerful antioxidant compound can medicate many diseases such as cardiovascular, kidney, liver and reproductive system disorders. With the increasing environmental pollution that has a direct adverse effect on male fertility, the use of this compound is able to positively function on human fertility health. In this study, we have been collected the main data of scientific articles (1994-2020) about N-acetyl cysteine effects. By searching in the scientific databases of PubMed, Google Scholar, Science Direct, Wiley and Web of Science, related articles were extracted. As a result, all observations have confirmed that N-acetyl cysteine can improve and normalise the spermatogenesis in the male reproduction system.

This in vitro study aimed to measure the ameliorative effect of L-carnitine against apoptosis, DNA fragmentation, membrane integrity and lipid peroxidation of spermatozoa from men with asthenoteratozoospermia (ATS). L-carnitine has an impressive effect on boosting the quality and quantity of spermatozoa and also can prevent apoptosis induction. For this purpose, semen samples were collected from 50 ATS men. Semen was divided into control and L-carnitine (0.5 mg/ml) groups at 2, 4, 6 and 24 hr. Concentrating on the reasons for apoptosis is an arduous process, but in the present research for this evaluation, mitochondrial membrane potential (MMP), DNA fragmentation by TUNEL and SCD methods, and lipid peroxidation were carried out. Also, sperm viability was performed. In the control group, MDA levels were increased significantly at 6 hr; however, sperm viability was decreased significantly at 4 and 6 hr. Moreover, in the L-carnitine group, TUNEL, SCD and MDA levels were decreased significantly and MMP and viability were increased significantly compared with the control group. In this writers' view, in vitro L-carnitine treatment can downregulate apoptosis in men with ATS.

Sterility makes laborious and obstacles to women and men, which has motived many problems in social members (Makker et al., 2009). Approximately, 10%-15% of couples are doomed to infertile (Fanaei et al., 2014). ATS is one of the whys and the wherefores for infertility in men (WHO, 2010). They have spermatozoa with motility less than %40 and abnormal morphology more than %96 (WHO, 2010). The previous study has shown the semen of ATS men produce high levels of ROS compared to normal men (Ghafarizadeh, Vaezi, Shariatzadeh & Malekirad, 2018). Lack of sufficient antioxidant levels in semen and mitochondrial dysfunction can be the reason for increase ROS (Fanaei

Human embryo cryopreservation is widely used in ART Programs, as it allows embryos to be stored without deterioration until needed [1]. Human pronuclear stage embryos (2PN) are routinely crupreserved by use of slow controled-rate freezing procedure. This method requires expensive equipments and longtime [2]. A simpler, quicker and less expensive alternative to