Melatonin attenuates Δ 9 -tetrahydrocannabinol-induced reduction in rat sperm motility and kinematics in-vitro

Etiology of Male Infertility: an Update

Spermatogenesis is a complex process of germ cell division and differentiation that involves extensive cross-talk between the developing germ cells and the somatic testicular cells. Defective endocrine signaling and/or intrinsic defects within the testes can adversely affect spermatogenic progression, leading to subfertility/infertility. In recent years, male infertility has been recognized as a global public health concern, and research over the last few decades has elucidated the complex etiology of male infertility. Congenital reproductive abnormalities, genetic mutations, and endocrine/metabolic dysfunction have been demonstrated to be involved in infertility/subfertility in males. Furthermore, acquired factors like exposure to environmental toxicants and lifestyle-related disorders such as illicit use of psychoactive drugs have been shown to adversely affect spermatogenesis. Despite the large body of available scientific literature on the etiology of male infertility, a substantial proportion of infertility cases are idiopathic in nature, with no known cause. The inability to treat such idiopathic cases stems from poor knowledge about the complex regulation of spermatogenesis. Emerging scientific evidence indicates that defective functioning of testicular Sertoli cells (Sc) may be an underlying cause of infertility/subfertility in males. Sc plays an indispensable role in regulating spermatogenesis, and impaired functional maturation of Sc has been shown to affect fertility in animal models as well as humans, suggesting abnormal Sc as a potential underlying cause of reproductive insufficiency/failure in such cases of unexplained infertility. This review summarizes the major causes of infertility/subfertility in males, with an emphasis on infertility due to dysregulated Sc function.

Psychoactive drugs and male fertility: impacts and mechanisms

Although psychoactive drugs have their therapeutic values, they have been implicated in the pathogenesis of male infertility. This study highlights psychoactive drugs reported to impair male fertility, their impacts, and associated mechanisms. Published data from scholarly peer-reviewed journals were used for the present study. Papers were assessed through AJOL, DOAJ, Google Scholar, PubMed/PubMed Central, and Scopus using Medical Subjects Heading (MeSH) indexes and relevant keywords. Psychoactive drugs negatively affect male reproductive functions, including sexual urge, androgen synthesis, spermatogenesis, and sperm quality. These drugs directly induce testicular toxicity by promoting ROS-dependent testicular and sperm oxidative damage, inflammation, and apoptosis, and they also suppress the hypothalamic-pituitary-testicular axis. This results in the suppression of circulating androgen, impaired spermatogenesis, and reduced sperm quality. In conclusion, psychoactive drug abuse not only harms male sexual and erectile function as well as testicular functions, viz., testosterone concentration, spermatogenesis, and sperm quality, but it also alters testicular histoarchitecture through a cascade of events via multiple pathways. Therefore, offering adequate and effective measures against psychoactive drug-induced male infertility remains pertinent.

Effect of In Vitro Addition of Melatonin and Glutathione on Seminal Parameters of Rams in Diluted Semen and after Thawing

The present study aimed to evaluate the effects of melatonin (MLT), glutathione (GSH), and their combination on ram semen quality after thawing. During eight weekly sessions, semen from three Merino rams was pooled, diluted with an egg-yolk-based semen extender, and divided into four groups: control, 1 mM MLT, 5 mM GSH, and 1 mM MLT + 5 mM GSH. Diluted semen was evaluated before and after the freezing process. The supplementation of diluted semen with GSH at 5 mM had a deleterious effect on total motility progressive (TPM), curvilinear velocity (VCL), straight-line velocity (VSL), average-path velocity (VAP), linearity (LIN), and straightness (STR) and increased slow spermatozoa (%). MLT at 1 mM also had a negative effect on TPM, VSL, and STR in diluted semen. In thawed semen, 1 mM MLT increased the TPM compared with the control group. VSL was lower in the 5 mM GSH group than in the 1 mM MLT group. Additionally, the combination of both antioxidants attenuated the negative effect of 5 mM GSH on TPM, VSL, and BCF. These results indicate that 5 mM GSH impairs or does not improve sperm kinetic parameters in either diluted or thawed semen. They also suggest that MLT combined with GSH plays a protective role against these effects.

Intertwined associations between oxidative and nitrosative stress and endocannabinoid system pathways: Relevance for neuropsychiatric disorders

The endocannabinoid system (ECS) appears to regulate metabolic, cardiovascular, immune, gastrointestinal, lung, and reproductive system functions, as well as the central nervous system. There is also evidence that neuropsychiatric disorders are associated with ECS abnormalities as well as oxidative and nitrosative stress pathways. The goal of this mechanistic review is to investigate the mechanisms underlying the ECS's regulation of redox signalling, as well as the mechanisms by which activated oxidative and nitrosative stress pathways may impair ECS-mediated signalling. Cannabinoid receptor (CB)1 activation and upregulation of brain CB2 receptors reduce oxidative stress in the brain, resulting in less tissue damage and less neuroinflammation. Chronically high levels of oxidative stress may impair CB1 and CB2 receptor activity. CB1 activation in peripheral cells increases nitrosative stress and inducible nitric oxide (iNOS) activity, reducing mitochondrial activity. Upregulation of CB2 in the peripheral and central nervous systems may reduce iNOS, nitrosative stress, and neuroinflammation. Nitrosative stress may have an impact on CB1 and CB2-mediated signalling. Peripheral immune activation, which frequently occurs in response to nitro-oxidative stress, may result in increased expression of CB2 receptors on T and B lymphocytes, dendritic cells, and macrophages, reducing the production of inflammatory products and limiting the duration and intensity of the immune and oxidative stress response. In conclusion, high levels of oxidative and nitrosative stress may compromise or even abolish ECS-mediated redox pathway regulation. Future research in neuropsychiatric disorders like mood disorders and deficit schizophrenia should explore abnormalities in these intertwined signalling pathways.

Cannabis sativa and/or melatonin do not alter brain lipid but alter oxidative mechanisms in female rats

Background

Lipid profile and redox status play a role in brain (dys)functions. Cannabinoid and melatonergic systems operate in the brain and contribute to brain (patho)physiology, but their roles in the modulation of brain lipid and redox status are not well-known. We studied the effect of ethanol extract of Cannabis sativa (CS) and/or melatonin (M) on the lipid profile and anti-oxidant system of the rat brain.

Methods

We randomly divided twenty-four (24) female Wistar rats into 4 groups (n = 6 rats each). Group 1 (control) received distilled water mixed with DMSO. Groups II–IV received CS (2 mg/kg), M (4 mg/kg), and co-administration of CS and M (CS + M) respectively via oral gavage between 8:00 am and 10:00 am once daily for 14 days. Animals underwent 12-h fasting after the last day of treatment and sacrificed under ketamine anesthesia (20 mg/kg; i.m). The brain tissues were excised and homogenized for assay of the concentrations of the total cholesterol (TC), triacylglycerol (TG), high-density lipoprotein cholesterol (HDL-C), nitric oxide (NO), malondialdehyde (MDA), and the activities of glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and acetylcholinesterase (AChE). One-way analysis of variance (ANOVA) was used to compare means across groups, followed by the least significant difference (LSD) post-hoc test.

Results

CS and/or M did not affect the lipid profile parameters. However, CS increased the G6PD (from 15.58 ± 1.09 to 21.02 ± 1.45 U/L; p = 0.047), GPx (from 10.47 ± 0.86 to 17.71 ± 1.04 U/L; p = 0.019), and SOD (from 0.81 ± 0.02 to 0.90 ± 0.01 μM; p = 0.007), but decreased NO (from 9.40 ± 0.51 to 6.75 ± 0.21 μM; p = 0.010) and had no effect on MDA (p = 0.905), CAT (p = 0.831), GR (p = 0.639), and AChE (p = 0.571) in comparison with the control group. M augmented the increase in G6PD (from 21.02 ± 1.45 U/L to 27.18 ± 1.81 U/L; p = 0.032) and decrease in NO (from 6.75 ± 0.21 to 4.86 ± 0.13 μM; p = 0.034) but abolished the increase in GPx (from 17.71 ± 1.04 to 8.59 ± 2.06 U/L; p = 0.006) and SOD (from 0.90 ± 0.01 to 0.70 ± 0.00 μM; p = 0.000) elicited by CS in the rat brain in comparison with the CS group.

Conclusions

CS and M do not alter brain lipid profile. Our data support the contention that CS elicits an anti-oxidative effect on the brain tissue and that CS + M elicits a pro-oxidant effect in rat brain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42238-021-00095-9.

Codeine-induced sperm DNA damage is mediated predominantly by oxidative stress rather than apoptosis

ABSTRACTBackground: Opioids have been implicated to induce infertility. Although codeine remains the most used opioid for recreational purpose, no study has documented its effect on sperm quality. Elucidating the effect of codeine on sperm cells and the associated mechanisms may provide an insight into preventing drug-induced sperm damage. Twenty-one New Zealand white rabbits were randomized into three groups; control and codeine-treated. The codeine-treated groups received either 4 or 10mg/kg b.w of codeine for six weeks.Results: Codeine treatment led to significant decrease in sperm count, motility, viability, normal morphology, and sperm membrane integrity. This was associated with significant rise in sperm DNA fragmentation, oxidative damage, and caspase 3 activity. The percentage of sperm DNA fragmentation correlates positively with 8-hydroxy-2'-deoxyguanosine, a biomarker of oxidative DNA damage, and caspase 3 activity, a biomarker of apoptosis. The observed correlation was stronger between sperm DNA fragmentation and oxidative DNA damage than sperm DNA fragmentation and caspase 3 activity.Conclusion: This study revealed that chronic codeine exposure causes sperm DNA fragmentation and poor sperm quality primarily via oxidative stress rather than activation of caspase 3-dependent apoptosis. Findings of the present study may explain drug-induced male factor infertility, particularly, those associated with opioid use.

Microplastics: A Threat for Male Fertility

Much of the planet is swimming in discarded plastic, which is harming animal and possibly human health. Once at sea, sunlight, wind, and wave action break down plastic waste into small particles: the microplastics (MPs). Currently, particular attention has been drawn to their effects on aquatic environments but the health risks, especially in mammals, are poorly known. These non-biodegradable materials can act as a vector for environmental pollutants, can be ingested by humans in food and water, and can enter and accumulate in human tissues with a possible risk for heath. Recent studies revealed the deleterious effects of MPs exposure in male reproduction and sperm quality, making them a potential hazard to reproductive success. This manuscript summarizes the main changes in sperm quality along the lifespan and the upcoming studies on the effects of MPs in male fertility in mammals.

Vitamin C ameliorates tetrahydrocannabinol-induced spermatotoxicity in-vitro

BACKGROUND

We investigated the in-vitro effects of vitamin C on delta-9-tetrahydrocannabinol (THC) -induced reduction in spermatozoa motility and kinematics.

METHODS

Six rats were used for the study. Semen from each of the 6 rats was randomly divided into 6 groups such that each rat's semen was in all of the groups. Groups I-III received placebo, THC (1 mM), and vitamin C (5 mM) respectively. Group IV was pre-treated with cannabinoid receptors' blockers (CBs-) 1 and 2, followed by THC. Groups V and VI received THC and vitamin C, but group VI was additionally pre-treated with CBs-.

RESULTS

The spermatozoa progressive motility, average path velocity (VAP), curvilinear velocity (VCL), straight-line velocity (VSL), amplitude of lateral head (ALH) and beat cross frequency (BCF) were reduced by THC (6.08 ± 1.16%; 5.64 ± 0.82 μm/s; 6.96 ± 0.74 μm/s; 2.75 ± 0.23 μm/s; 0.31 ± 0.02 μm; and 0.78 ± 0.08 Hz respectively) but increased by vitamin C (51.20 ± 1.32%; 17.90 ± 0.21 μm/s; 25.11 ± 0.96 μm/s; 8.80 ± 0.27 μm/s; 0.75 ± 0.01 μm; and 3.15 ± 0.03 Hz respectively) when compared to control (39.72 ± 0.38%; 13.70 ± 0.29 μm/s; 18.04 ± 0.58 μm/s; 7.54 ± 0.34 μm/s; 0.65 ± 0.02 μm; and 2.79 ± 0.01 Hz respectively). Vitamin C inhibited the THC-induced reduction in these parameters (37.36 ± 0.73%; 10.98 ± 0.45 μm/s; 13.58 ± 0.30 μm/s; 7.11 ± 0.22 μm/s; 0.58 ± 0.01 μm; and 2.60 ± 0.01 Hz respectively) in the absence of CBs- 1 and 2, and even caused additional increases in progressive motility (49.54 ± 1.01%), VAP (15.70 ± 0.38 μm/s) and VCL (22.53 ± 0.29 μm/s) above the control levels with CBs-.

CONCLUSION

Vitamin C ameliorates the THC-induced reduction in spermatozoa motility in-vitro by modulation of their kinematics.

Melatonin protects sperm cells of Capoeta trutta from toxicity of titanium dioxide nanoparticles

In this study, it was aimed to determine the protective effects of melatonin (0.01, 0.1, and 1 mM) against 10 mg/L titanium dioxide nanoparticles (TiO2-NPs) on kinematic and oxidative indices in the sperm cells of Capoeta trutta. Therefore, TiO2 nanoparticles were synthesized primarily within the scope of the study. The synthesized nanoparticles were characterized by structurally different techniques. Then, melatonin and TiO2 were applied to Capoeta trutta sperm cells by in vitro. According to our data, all doses of melatonin showed protective effects on all velocities of sperm cells such as the straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) against TiO2-NPs, while 0.1 and 1 mM doses of melatonin improved the VSL value. Although TiO2-NPs increased total glutathione (tGSH), malondialdehyde (MDA) lipid peroxidation, and superoxide dismutase (SOD) compared to the control group, there were positive treatment effects for all doses of melatonin on antioxidant capacity of sperm cells. At the end of this research, it is suggested that over 0.1 mM dose of melatonin improves the velocity of sperm cells and it plays a protective role against the toxic effects of TiO2-NPs.

Cannabinoid-deficient Benin republic hemp (Cannabis sativa L.) improves semen parameters by reducing prolactin and enhancing anti-oxidant status

BACKGROUND

Nigerian Cannabis sativa (hemp) causes male gonadotoxicity by inducing hyperprolactinemia, down-regulation of hypothalamic-pituitary-testicular axis, and oxidative stress. Benin republic hemp has been preferred by illicit users in Nigeria but its effect on male fertility is not understood. This study determined and compared the compositions of Benin republic hemp ethanol extract (BHE) and Nigerian hemp. The effects of BHE on semen parameters, reproductive hormones, and anti-oxidant status, and the possibility of bromocriptine (prolactin inhibitor) to abolish hemp-induced toxicities in rats were also investigated.

METHODS

Thirty-six male Wistar rats were blindly randomized into 6 oral treatment groups (n = 6 each). Groups I (control) and II received normal saline and bromocriptine (3 mg/kg) respectively. Groups III and IV received 2 mg/kg of BHE alone and in combination with bromocriptine respectively, while groups V and VI received 10 mg/kg BHE alone and in combination with bromocriptine respectively. Comparisons among the groups were done by one-way analysis of variance, followed by post-hoc Tukey multiple comparison test. Statistical significance was considered at p < 0.05.

RESULTS

The BHE has no cannabichromene and tetrahydrocannabinol but a very small quantity of cannabinol and higher quantity of fatty acids when compared to Nigerian hemp. Both doses of BHE increased sperm count, morphology and viability but not motility. Co-administration of BHE with bromocriptine lowered sperm count but increased sperm morphology and viability. Bromocriptine and/or BHE caused reduction in the plasma prolactin level, increase in the plasma superoxide dismutase activity, but no significant change in the plasma gonadotropin releasing hormone, follicle stimulating hormone (except for the increase in rats that received bromocriptine+ 10 mg/kg BHE), luteinizing hormone, estradiol, malondialdehyde and glutathione peroxidase. The 10 mg/kg BHE or bromocriptine+BHE (both doses) increased total anti-oxidant capacity and catalase.

CONCLUSIONS

The BHE improves semen parameters by reducing plasma prolactin and enhancing plasma anti-oxidant status. Its pro-fertility potential might be associated with its deficiency in the widely known gonadotoxic phytocannabinoids.