Cannabis impacts sperm counts, motility in two generations of mice


Date:
December 2, 2021
Source:
Washington State University
Summary:
An intense but short-term exposure to cannabis vapor lowered sperm
counts and slowed sperm movement, or motility, not only in the
directly exposed male mice but also in their sons, according to a
new study. The findings build on other human and animal research,
showing that cannabis can impede male reproductive function. The
current study uses more controlled circumstances than human
studies, which often have to rely on surveys, and is the first known
reproductive study to use vaporized whole cannabis in mice, which is
the more common form humans use. Previous animal studies use other
administration methods such as injections of tetrahydrocannabinol
(THC), the main psychoactive component of cannabis.



FULL STORY ==========================================================================
An intense but short-term exposure to cannabis vapor lowered sperm counts
and slowed sperm movement, or motility, not only in the directly exposed
male mice but also in their sons.


==========================================================================
The Washington State University study, published in the journal
Toxicological Sciences, builds on other human and animal studies, showing
that cannabis can impede male reproductive function. The current study
uses more controlled circumstances than human studies, which often have
to rely on surveys, and is the first known reproductive study to use
vaporized whole cannabis in mice, which is the more common form humans
use. Previous animal studies use other administration methods such as injections of tetrahydrocannabinol (THC), the main psychoactive component
of cannabis.

More research needs to be done, but the study's generational findings
should give cannabis users pause, said Kanako Hayashi, the paper's corresponding author.

"This is a warning flag. You may take cannabis for some kind of momentary stress, but it could affect your offspring," said Hayashi, who is an
associate professor in WSU's School of Molecular Biosciences.

Human sperm counts have declined by as much as 59% in recent decades,
according to some estimates. There are likely many reasons for this
decline, Hayashi said, but this study adds to the evidence that cannabis
use may be detrimental to male reproductive function.

For this study, researchers studied 30 adult male mice. They exposed 15
of them to cannabis vapor three times a day for ten days -- an intense
amount but one that mimics the cannabis intake of frequent cannabis
users. The researchers then compared sperm counts and motility in those
mice to the unexposed control group. They found that immediately after
the exposure period, the mice's sperm motility decreased, and after one
month, sperm counts were lower.

The researchers bred several of the male mice to unexposed female
mice. The male progeny of the exposed group also showed lowered sperm
count and motility.

Cannabis-exposed sons also showed evidence of DNA damage and disruption
related to sperm cell development.

"We were not expecting that the sperm would be completely gone or that
motility would be completely offset, but the reduction in sperm count
and motility of the offspring, the sons, is probably a direct effect of
the cannabis exposure to father," said Kanako.

A third-generation, the grandsons of the exposed male mice, did not show
the same impacts, however, which suggests that the cannabis exposure
impacted the second-generation mice at a developmental stage.

Hayashi and her colleagues are currently testing the theory that cannabis exposure to mice in utero would have deeper generational effects, as
the drug would affect the formation of the mice's reproductive system
that could be passed down.

The current study was supported in part by funds provided for medical and biological research by the State of Washington Initiative Measure No. 171 ========================================================================== Story Source: Materials provided by Washington_State_University. Original written by Sara Zaske. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Mingxin Shi, Esther M Langholt, Logan C Butler, Madeleine E
Harvey, Emma
C Wheeler, Liang Zhao, James A MacLean, II, Yeongseok Oh, Emily
Sabrowsky, Sue Yu, Shane Watson, Jon F Davis, Kanako Hayashi. Vapor
cannabis exposure generationally affects male reproductive functions
in mice. Toxicological Sciences, 2021 DOI: 10.1093/toxsci/kfab137 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211202092947.htm

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