Cannabis found to impact fertility in two generations of mice

The study cites past publications that have suggested similar implications for human users.

  (photo credit: PIXABAY)
(photo credit: PIXABAY)

A recent study published by Washington State University revealed that male mice exposed to cannabis vapor experienced negative impacts on their sperm counts and motility. 

The peer-reviewed study was the first to utilize cannabis in a vaporized form rather than injecting mice with THC, the main psychoactive compound in cannabis, directly. Vaporized cannabis is also one of the most common forms of the plant that humans consume, and the study cites past publications that have suggested similar implications for human cannabis users.

Thirty adult male mice were divided into two groups of 15, the control group being exposed to clean air and the experimental group being exposed to vaporized cannabis three times a day for ten days. The mice were then bred with females that had not been exposed to any drug. The male offspring were then bred to produce a third generation of ‘grandsons’ to examine if effects of cannabis exposure would present in them as well. 

Tissue sampling and imaging demonstrated that the initial group of mice exposed to cannabis vapor had decreased sperm motility directly following exposure and lowered sperm counts one month later. The group’s male offspring showed similar results as well as “evidence of DNA damage and disruption related to sperm cell development.” 

The third generation of male offspring showed no evidence of decreased sperm count or motility, and testosterone levels in blood plasma weren’t found to be affected in any of the mice. These findings suggest that the impact on the second generation mouse ‘sons’ likely occurred “at a developmental stage.”

A man prepares a cigarette mixed with marijuana during Cannatech 2017, an annual global cannabis industry event, in Tel Aviv, Israel March 20, 2017. (credit: REUTERS/AMIR COHEN)A man prepares a cigarette mixed with marijuana during Cannatech 2017, an annual global cannabis industry event, in Tel Aviv, Israel March 20, 2017. (credit: REUTERS/AMIR COHEN)

The study explained that “many normal reproductive aspects are modulated by the [body’s] endocannabinoid system.” Certain natural lipids “are essential regulators in reproduction, including the hypothalamus-pituitary-gonad (HPG) axis, germ cell development and sperm functions. THC interferes with the cellular functions of sperm, oocyte and embryo.”

Kanako Hayashi, one of the study’s authors said in a Washington State University news release that cannabis users should exercise caution. "This is a warning flag. You may take cannabis for some kind of momentary stress, but it could affect your offspring," she explained.

Hayashi and other Washington State University researchers are currently examining the impacts of cannabis exposure in a new study of mice in utero.