Effects of cannabinoids on spermatogenesis in mice

Genotoxicity of selected cannabinoids in human lymphoblastoid TK6 cells

Natural non-psychoactive cannabinoids such as cannabigerol (CBG), cannabidiol (CBD), cannabichromene (CBC), cannabidivarin (CBDV), and cannabinol (CBN) are increasingly consumed as constituents of dietary products because of the health benefits claims. Cannabinoids may reduce certain types of pain, nausea, and anxiety. Anti-inflammatory and even anti-carcinogenic properties have been discussed. However, there are insufficient data available regarding their potential (geno-)toxic effects. Therefore, we tested CBG, CBD, CBC, CBDV, and CBN for their genotoxic potential and effects on mitosis and cell cycle in human lymphoblastoid TK6 cells. The selected cannabinoids (except CBDV) induced increased micronuclei formation, which was reduced with the addition of a metabolic activation system (S9 mix). CBDV induced micronuclei only after metabolic activation. Mitotic disturbances were observed with all tested cannabinoids, while G1 phase accumulation of cells was observed for CBG, CBD and CBDV. The genotoxic effects occurred at about 1000-fold higher concentrations than are reported as blood levels from human consumption. However, the results clearly indicate a need for further research into the genotoxic effects of cannabinoids. The mechanism of the mitotic disturbance, the shape of the dose-response curves and the possible effects of mixtures of cannabinoids are aspects which need clarification.

Delta-9 THC can be detected and quantified in the semen of men who are chronic users of inhaled cannabis

PURPOSE

The purpose of this proof-of-concept study was to determine whether delta-9-tetrahydrocannabinol (THC) and THC metabolites (11-OH THC and THC-COOH) can be detected in semen.

METHODS

Twelve healthy men aged 18-45 years who identified as chronic and heavy users of inhaled cannabis were recruited. THC and THC metabolite levels were measured in serum, urine, and semen of the participants. Semen analyses were performed. Serum reproductive hormones were measured.

RESULTS

The median age and BMI of participants were 27.0 years and 24.7 kg/m², respectively. Over half the participants were daily users of cannabis for over 5 years. Serum reproductive hormones were generally within normal ranges, except prolactin, which was elevated in 6 of 12 participants (mean 13.9 ng/mL). The median sperm concentration, motility, and morphology were 75.5 million/mL, 69.5%, and 5.5%, respectively. Urinary THC-COOH was detected in all 12 participants, and at least one serum THC metabolite was present in 10 of 12 participants. Two semen samples had insufficient volume to be analyzed. THC was above the reporting level of 0.50 ng/mL in the semen of two of the remaining participants. Seminal THC was moderately correlated with serum levels of THC (r = 0.66), serum 11-OH THC (r = 0.57), and serum THC-COOH (r = 0.67). Seminal delta-9 THC was not correlated with urinary cannabinoid levels or semen analysis parameters.

CONCLUSION

This is the first study to identify and quantify THC in human semen, demonstrating that THC can cross the blood-testis barrier in certain individuals. Seminal THC was found to be moderately correlated with serum THC and THC metabolites.

Cannabis and Male Fertility: A Systematic Review

PURPOSE

With cannabis consumption on the rise and use prominent among males of reproductive age it is essential to understand the potential impact of cannabis on male fertility. We reviewed the literature regarding the effects of cannabis on male fertility.

MATERIALS AND METHODS

We performed a literature search using PubMed®/MEDLINE® to identify relevant studies of the effects of cannabis on male fertility. Relevant studies were identified and reviewed.

RESULTS

The strongest evidence of cannabis induced alterations in male fertility is in the category of semen parameters. Research supports a role for cannabis in reducing sperm count and concentration, inducing abnormalities in sperm morphology, reducing sperm motility and viability, and inhibiting capacitation and fertilizing capacity. Animal models demonstrate a role for cannabis in testicular atrophy, and reduced libido and sexual function but to our knowledge these results have not yet been replicated in human studies. Studies of hormonal changes suggest inconclusive effects on testosterone levels, lowered luteinizing hormone levels and unchanged follicle-stimulating hormone levels.

CONCLUSIONS

Current research suggests that cannabis may negatively impact male fertility. Further studies are needed to validate that robust findings in animal models will carry over into human experience. Clinicians should be aware of these potential effects when prescribing medical marijuana therapies to men of reproductive age, and they should consider the degree of cannabis use as a possible component of a complete male infertility workup.

Smoke, alcohol and drug addiction and male fertility

In recent decades, the decline in human fertility has become increasingly more worrying: while therapeutic interventions might help, they are vexing for the couple and often burdened with high failure rates and costs. Prevention is the most successful approach to fertility disorders in males and females alike. We performed a literature review on three of the most common unhealthy habits - tobacco, alcohol and drug addiction - and their reported effects on male fertility. Tobacco smoking is remarkably common in most first-world countries; despite a progressive decline in the US, recent reports suggest a prevalence of more than 30% in subjects of reproductive age - a disturbing perspective, given the well-known ill-effects on reproductive and sexual function as well as general health. Alcohol consumption is often considered socially acceptable, but its negative effects on gonadal function have been consistently reported in the last 30 years. Several studies have reported a variety of negative effects on male fertility following drug abuse - a worrying phenomenon, as illicit drug consumption is on the rise, most notably in younger subjects. While evidence in these regards is still far from solid, mostly as a result of several confounding factors, it is safe to assume that cessation of tobacco smoking, alcohol consumption and recreational drug addiction might represent the best course of action for any couple trying to achieve pregnancy.

Marijuana, phytocannabinoids, the endocannabinoid system, and male fertility

Marijuana has the highest consumption rate among all of the illicit drugs used in the USA, and its popularity as both a recreational and medicinal drug is increasing especially among men of reproductive age. Male factor infertility is on the increase, and the exposure to the cannabinoid compounds released by marijuana could be a contributing cause. The endocannabinoid system (ECS) is deeply involved in the complex regulation of male reproduction through the endogenous release of endocannabinoids and binding to cannabinoid receptors. Disturbing the delicate balance of the ECS due to marijuana use can negatively impact reproductive potential. Various in vivo and in vitro studies have reported on the empirical role that marijuana plays in disrupting the hypothalamus-pituitary-gonadal axis, spermatogenesis, and sperm function such as motility, capacitation, and the acrosome reaction. In this review, we highlight the latest evidence regarding the effect of marijuana use on male fertility and also provide a detailed insight into the ECS and its significance in the male reproductive system.

Effects of chronic bhang (cannabis) administration on the reproductive system of male mice

BACKGROUND

The purpose of this study was to investigate the effect of chronic uptake of bhang, prepared from the Cannabis sativa, on male reproductive physiology in adult male Parkes strain (P) mice. An attempt was also made to investigate the presence of cannabinoid 1 (CB1) and cannabinoid 2 (CB2) receptors, and fatty acid amide hydrolase (FAAH) in the testis and to evaluate any changes in it resulting from chronic intake of bhang in mice.

METHODS AND RESULTS

Adult male mice were given bhang (3 or 6 mg/kg body weight/day) orally for 36 consecutive days. Chronic intake of bhang caused regressive changes in the testes and suppressed sperm count, viability and motility. Bhang intake also caused significant decline in circulating testosterone level due to decline in testicular 3β HSD enzyme activity. An immunohistochemical study demonstrated the presence of CB1, CB2 and FAAH in the testis of mice. The present study also showed significant variation in the CB1 and CB2 receptors and FAAH protein levels in testes of mice exposed to bhang. These suppressive effects may be due to inhibitory effect of bhang on pituitary expression of gonadotrophin releasing hormone (GnRH) I receptor protein. Treatment of testes with bhang in vitro significantly decreased testicular luteinizing hormone receptor (LHR) and FAAH expression suggesting direct action of bhang on testicular activity.

CONCLUSIONS

The findings of this study thus suggest that bhang may impair fertility in male mice through alteration in the testicular endocannabinoid system and that chronic bhang exposure in humans would be predicted to alter male fertility.

Endocrine effects of marijuana

In the 35 years since the active compound of marijuana, delta9-tetrahydrocannabinol, was isolated, the psychological and physiological impact of marijuana use has been actively investigated. Animal models have demonstrated that cannabinoid administration acutely alters multiple hormonal systems, including the suppression of the gonadal steroids, growth hormone, prolactin, and thyroid hormone and the activation of the hypothalamic-pituitary-adrenal axis. These effects are mediated by binding to the endogenous cannabinoid receptor in or near the hypothalamus. Despite these findings in animals, the effects in humans have been inconsistent, and discrepancies are likely due in part to the development of tolerance. The long-term consequences of marijuana use in humans on endocrine systems remain unclear.

Pharmacokinetics of THC in brain and testis, male gametotoxicity and premature apoptosis of spermatozoa

An earlier report described the pharmacokinetics of delta-9 THC and the resulting brain function responses. In the present studies the pharmacokinetics of THC in plasma, brain and testis were related to impairment of spermatogenesis. THC- containing preparations, whatever their route of administration, were associated with the induction of gametotoxicity in all species studied including man. The pharmacokinetics and molecular binding of THC is similar in all experimental models. Concentrations of THC in plasma, fat, testis, brain and spleen were measured following administration of tracer amounts of C(14) delta-8 THC labelled at the C(11) position. Rats were administered 2 microCi of the tracer by i.m. injection, and killed at regular intervals after a single or multiple dose of the label. After a single dose, the maximal radioactivity was reached in brain after 2 and 4 h and amounted to 0.06% of the administered dose. In the testis, the concentration did not exceed 0.023% of the administered dose. In epididymal fat, the total radioactivity after 4 h was five times higher than in the brain and after 24 h it was eight times greater. After multiple injections of C(14) THC, concentrations of the drug remained low in the plasma, brain and testis not exceeding 2-7 ng/g, but the epididymal fat tracer concentration was 40-80 times higher. Plasma concentrations of C(14) THC were of the same magnitude as those measured by GCMS in the plasma of men exposed to marihuana smoke or THC, and in whom alterations of spermatogenesis were observed. In these studies, plasma THC ranged from 9.5x10(12) M to 2.4x10(14) M. These data illustrate the efficiency of the blood-brain barrier and blood-testicular barrier in limiting the storage of THC into brain and testis. During chronic exposure to THC the pharmacokinetic molecular mechanisms which limit the storage of THC in the brain and testis are not sufficient to prevent a persistent deregulation of membrane signalling and the induction of functional and morphological changes which reflect a premature apoptosis of spermatogenic cells. Long term, longitudinal epidemiological studies have reported decreased spermatogenesis in healthy, fertile adult males. But no study has been initiated to relate the oligospermia of this population to the consumption of widely used psychoactive drugs.