Brandie Leary
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Likewise, we show here that supplementation of infertile individuals with 600 mg/day of NAC significantly reduces DNA fragmentation from 19.34 ± 0.47 before treatment to 15.14 ± 0.46 after treatment and also improves sperm protamine content. Most of such clinical studies have evaluated men with high levels of sperm DNA damage. N-acetylcysteine (NAC) is a thiol-based antioxidant that plays an important role in the protection of cellular constituents against oxidative damage.
When NAC is ingested and absorbed, it undergoes deacetylation, resulting in the release of cysteine, which is then free to serve as a precursor in glutathione synthesis. Conditions such as fatty liver disease, hepatitis, and cirrhosis are often characterized by decreased glutathione levels. The liver is exposed to high levels of oxidative stress due to its metabolic functions. NAC supports detoxification primarily through its role as a precursor to glutathione, a powerful antioxidant involved in the body's natural detoxification processes. NAC is used as a precursor for glutathione and possesses both antioxidant and mucolytic properties.
Epigenetic and environmental changes are various in different countries, and this issue may lead to different responses to NAC supplementation(Reference Diamanti-Kandarakis, Kandarakis and Legro33). A decline in TT was reported in both studies(Reference Elnashar, Fahmy and Mansour21,Reference Chandil, Pande and Sen27) . Also, it has been shown that a longer duration of supplementation might be more effective.
We utilised a random-effects model to get the overall effect size if the amount of between-study heterogeneity was significant. If the trial had ‘low risk’ for all domains, a high-quality study was considered a low risk of bias. The Cochrane Collaboration’s risk of bias tool was employed to assess the risk of bias for each study(Reference Higgins, Altman and Gøtzsche19). Then, relevant studies were assessed to ensure the suitability of a study for full-text assessment. Numerous studies have indicated that NAC is effective for the induction of ovulation and pregnancy rates in PCOS patients.
Glutathione also acts as an antioxidant, neutralizing inflammatory molecules called free radicals or ROS that can damage cellular structures. It participates in conjugation reactions in the liver, where toxins are bound to glutathione to make them water-soluble and more easily excreted from the body. Glutathione is a tripeptide composed of three amino acids, glutamate, glycine, and cysteine.
NAC has antioxidant properties as a prodrug of intracellular CySH (intracellular increase in CySH concentration) with a subsequent increase in GSH. Therefore, periods of continuous supplementation 24,27,30, of at least 3 days, would provide a higher concentration of NAC, and therefore a direct antioxidant effect, assessed by TAC 24,30 or pro-antioxidant ratio . This may explain the differences in the results of the studies included in this systematic review 21,24,30. However, the study conducted by Christensen et al. reported no difference between the two groups (IG, CG) after 1 day of NAC supplementation. However, there was no clear evidence of any beneficial effects of NAC supplementation on haematological markers, inflammatory response, and muscle behaviour. In general, participants supplemented with NAC showed significant improvements in exercise performance, antioxidant capacity, and glutathione homeostasis.
Male age and duration of infertility were recorded at time of the study. All individuals gave informed consent prior to participation in the study. A total of 50 infertile men with terato-asthenozoospermia and a mean age of 25–40 years were enrolled in the unit of ACECR Infertility Research Center, Qom, Iran, in 2018.
Indeed, oxidative stress hampers chromatin reprogramming including DNA methylation, which has important consequences on the formation of the protamine shield protecting DNA from oxidative stress and thereby DNA damage. Thus, NAC reduced the severity of oxidative stress leading to reduced lipid peroxidation and DNA fragmentation as verified by MDA and TUNEL assay. Spermatogenesis is highly controlled by the hormonal milieu of the testis and any alteration in the hormonal profile, besides influencing the rate and quality of spermatogenesis, may deeply affect chromosomal ploidy and integrity of sperm chromatin . Higher amounts of protamines in sperm mean that a relaxed chromatin state has been converted to a compact and stable structure that reduces the accessibility of ROS to DNA. In addition, significant inverse correlations were observed between the percentage of TUNEL-positive cells versus sperm motility or morphology, indicating that NAC protects sperm chromatin integrity and reduces DNA fragmentation.
When NAC is ingested and absorbed, it undergoes deacetylation, resulting in the release of cysteine, which is then free to serve as a precursor in glutathione synthesis. Conditions such as fatty liver disease, hepatitis, and cirrhosis are often characterized by decreased glutathione levels. The liver is exposed to high levels of oxidative stress due to its metabolic functions. NAC supports detoxification primarily through its role as a precursor to glutathione, a powerful antioxidant involved in the body's natural detoxification processes. NAC is used as a precursor for glutathione and possesses both antioxidant and mucolytic properties.
Epigenetic and environmental changes are various in different countries, and this issue may lead to different responses to NAC supplementation(Reference Diamanti-Kandarakis, Kandarakis and Legro33). A decline in TT was reported in both studies(Reference Elnashar, Fahmy and Mansour21,Reference Chandil, Pande and Sen27) . Also, it has been shown that a longer duration of supplementation might be more effective.
We utilised a random-effects model to get the overall effect size if the amount of between-study heterogeneity was significant. If the trial had ‘low risk’ for all domains, a high-quality study was considered a low risk of bias. The Cochrane Collaboration’s risk of bias tool was employed to assess the risk of bias for each study(Reference Higgins, Altman and Gøtzsche19). Then, relevant studies were assessed to ensure the suitability of a study for full-text assessment. Numerous studies have indicated that NAC is effective for the induction of ovulation and pregnancy rates in PCOS patients.
Glutathione also acts as an antioxidant, neutralizing inflammatory molecules called free radicals or ROS that can damage cellular structures. It participates in conjugation reactions in the liver, where toxins are bound to glutathione to make them water-soluble and more easily excreted from the body. Glutathione is a tripeptide composed of three amino acids, glutamate, glycine, and cysteine.
NAC has antioxidant properties as a prodrug of intracellular CySH (intracellular increase in CySH concentration) with a subsequent increase in GSH. Therefore, periods of continuous supplementation 24,27,30, of at least 3 days, would provide a higher concentration of NAC, and therefore a direct antioxidant effect, assessed by TAC 24,30 or pro-antioxidant ratio . This may explain the differences in the results of the studies included in this systematic review 21,24,30. However, the study conducted by Christensen et al. reported no difference between the two groups (IG, CG) after 1 day of NAC supplementation. However, there was no clear evidence of any beneficial effects of NAC supplementation on haematological markers, inflammatory response, and muscle behaviour. In general, participants supplemented with NAC showed significant improvements in exercise performance, antioxidant capacity, and glutathione homeostasis.
Male age and duration of infertility were recorded at time of the study. All individuals gave informed consent prior to participation in the study. A total of 50 infertile men with terato-asthenozoospermia and a mean age of 25–40 years were enrolled in the unit of ACECR Infertility Research Center, Qom, Iran, in 2018.
Indeed, oxidative stress hampers chromatin reprogramming including DNA methylation, which has important consequences on the formation of the protamine shield protecting DNA from oxidative stress and thereby DNA damage. Thus, NAC reduced the severity of oxidative stress leading to reduced lipid peroxidation and DNA fragmentation as verified by MDA and TUNEL assay. Spermatogenesis is highly controlled by the hormonal milieu of the testis and any alteration in the hormonal profile, besides influencing the rate and quality of spermatogenesis, may deeply affect chromosomal ploidy and integrity of sperm chromatin . Higher amounts of protamines in sperm mean that a relaxed chromatin state has been converted to a compact and stable structure that reduces the accessibility of ROS to DNA. In addition, significant inverse correlations were observed between the percentage of TUNEL-positive cells versus sperm motility or morphology, indicating that NAC protects sperm chromatin integrity and reduces DNA fragmentation.
