LEGALISATION of cannabis use in various states within the USA has seen the substance thrown into the national spotlight; however, the impact the drug can have on reproductive health is still widely debated. Now, new research from Duke Health, North Carolina, USA has shown that tetrahydrocannabinol (THC), the active ingredient in marijuana, can genetically alter the drug user’s sperm cells.
Building on previous research which has shown that many substances, such as tobacco smoke, pesticides, and flame retardants, can have an impact on the genetic structure of sperm, this new research explored the epigenetic effects of prolonged cannabis use in both human and murine models. The human study examined 24 men who had smoked marijuana at least weekly for the preceding 6 months, comparing their sperm to two groups of controls: those who had not used the drug in the last 6 months and no more than 10 times in their lifetime.
The results showed a correlation between the levels of THC present in the subject’s urine and genetic alteration to their sperm. Hundreds of genes were affected, many of which were associated with cellular pathways impacting cell growth that can become dysregulated in some cancers.
“We know that there are effects of cannabis use on the regulatory mechanisms in sperm DNA, but we do not know whether they can be transmitted to the next generation,” explained Prof Susan Murphy.
While the study was limited by the small sample size and the results confounded by other factors affecting sperm health (such as alcohol use, sleep, nutrition, etc.), this research showed that THC levels have an epigenetic impact on sperm. Larger studies are warranted to explore whether these effects are reversable following the cessation of marijuana use, as well as the whether these epigenetic changes are carried forward to the offspring.
“[…] the best advice would be to assume these changes are going to be there. We don’t know whether they are going to be permanent. I would say, as a precaution, stop using cannabis for at least 6 months before trying to conceive,” advised Prof Murphy.