Freezing of human spermatozoa is done to increase the success of assisted reproductive techniques (Agarwal & Majzoub, 2017). In the freezing method, intracellular ice crystal formation and the concentration of solute are problematic, and the survival of frozen cells depends on the type of cell and freezing rate (Tomás et al., 2019). One way to avoid damage by forming ice crystals is to use the vitrification method (Arav et al., 2018). In the vitrification method, freezing is performed by immersing the samples directly into the liquid nitrogen tank (Isachenko et al., 2018). This method reduces ice crystal formation and intracellular injuries (Adib et al., 2018). Vitrification is delivered in less time than conventional sperm freezing methods and is also safer and less costly (Horta et al., 2017; Spis et al., 2019). Evidence has shown that in semen, ROS are produced in the freezing and thawing processes. Although the average level of ROS can regulate sperm functions when it exceeds the detoxification level, it leads to oxidative stress (Lone et al., 2018). Free radicals from oxidative stress can disrupt motility after thawing, viability, cell membrane, mitochondrial membrane potential, DNA fragmentation, intracellular enzymatic activity, sperm function and fertility (Bustamante Filho et al., 2018; Zhang et al., 2019). Recent studies have indicated that ultra-rapid freezing reduces destructive effects on sperm

Background: Several studies have reported the association between polymorphisms in Matrix metalloproteinases (MMPs) gene family and risk of Multiple sclerosis (MS). However, the results have been inconsistent and inconclusive. To resolve this issue, here we performed a systematic review and meta-analysis of the MMP-91562 C/T (rs3918242), MMP-3 (− 1612 5A/6A), and MMP-2 (− 1306 C/T) polymorphisms and susceptibility to MS. Methods: We conducted a comprehensive systematic search in the major electronic database, including Scopus and PubMed to look up for relevant studies published before December 2019 that surveyed the association between the MMP-91562 C/T (rs3918242), MMP-3 (− 1612 5A/6A), and MMP-2 (− 1306 C/T) polymorphisms and susceptibility to MS. The level of association between the polymorphisms and susceptibility to MS in the polled analysis was determined by calculating the odds ratio (OR) and the corresponding 95% confidence interval (CI). Results: We found 15 studies containing 2430 MS subjects and 2304 controls. A statistically significant association was observed in the all five comparisons of the MMP-91562 C/T polymorphism and MS risk as follows: dominant model (

Objective: Amino acids can protect sperm structure in cryopreservation due to their antioxidant properties. Therefore, the present study aimed to investigate the protective effect of L-carnitine (LC) and N-acetyl cysteine (NAC) on motility parameters, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), DNA damage, and human sperm intracellular reactive oxygen species (ROS) during vitrification. Methods: Twenty normal human sperm samples were examined. Each sample was divided into six equal groups: LC (1 and 10 mM), NAC (5 and 10 mM), and cryopreserved and fresh control groups. Results: The groups treated with LC and NAC showed favorable findings in terms of motility parameters, DNA damage, and MMP. Significantly higher levels of intracellular ROS were observed in all cryopreserved groups than in the fresh group (p≤0.05). The presence of LC and NAC at both concentrations caused an increase in PMI, MMP, and progressive motility parameters, as well as a significant reduction in intracellular ROS compared to the control group (p≤0.05). The concentrations of the amino acids did not show any significant effect.Conclusion: LAC and NAC are promising as potential additives in sperm cryopreservation.

The main aim of this study was to assay the testicular H2S levels in the varicocele rat model and then to investigate the protective effects of NaHS on morphometric changes, sperm parameters, oxidative stress and apoptosis markers in rat's testis. D,L‐propargylglycine (PAG) was administrated to show the effects of cystathionine γ‐lyase enzyme (CSE) inhibition in the varicocele. Rats were assigned to four groups: (a) Sham, (b) varicocele, (c) varicocele + PAG and (d) varicocele + NaHS. Animals in varicocele + NaHS group received 30 µmol/L NaHS in drinking water for 56 days. In the varicocele + PAG group, animals received PAG 19 mg/kg twice a week. Morphometric assessment, oxidative stress markers, testicular H2S levels, sperm parameters, TUNEL assay and expression of Bax/Bcl2 were evaluated at the end of experiment. Testicular H2S levels were significantly decreased in varicocele group. NaHS significantly improved sperm parameters, morphometric characteristics and oxidative stress compared to varicocele group. Oxidative stress status deteriorated in the PAG group compared to the varicocele group. This study showed that a low testicular H2S level might play a critical role in male infertility. Thus, NaHS administration may be a promising treatment strategy for male infertility in varicocele. In addition, CSE may not be the only important enzyme in testicular H2S production.

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