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GDNF Brain Injection Reduces Cannabis Addiction Behavior and Reverses Sperm Damage in Rats

Animal StudyPreliminary evidence
The takeaway

Injecting glial cell line-derived neurotrophic factor (GDNF) into the brains of cannabis-addicted rats reduced anxiety, reversed abnormal sperm morphology, decreased sperm DNA damage, and improved sperm viability.

Reproductive biology researchers, addiction neuroscientists, and fertility specialists.

GDNF reduced cannabis-induced sperm DNA damage (p=0.0242)

What the researchers found

Cannabis-addicted rats showed increased anxiety, reduced germ cells, smaller testes/epididymis, altered sperm morphology, and increased DNA damage. GDNF treatment improved anxiety (p<0.05), reversed abnormal sperm morphology, improved sperm grading (grade C, p=0.0295), reduced DNA damage (p=0.0242), and enhanced viability. GDNF had limited effect on testis/epididymis size or germ cell counts.

Why it matters

Cannabis use is linked to male fertility problems, and GDNF is a key factor in spermatogenesis. This study shows GDNF can partially reverse cannabis-induced reproductive damage while also improving addiction-related behavior, suggesting a dual therapeutic target.

The numbers in context

15 rats; cannabis reduced germ cells (p=0.0006) and organ size (p=0.003); GDNF reversed sperm morphology (p=0.0016), grade C sperm (p=0.0295), DNA damage (p=0.0242).

How the study worked

15 male Wistar rats in 3 groups: control, cannabis-addicted, and cannabis-addicted + GDNF. Cannabis addiction induced via smoking machine (0.25g per 5 rats). GDNF delivered by stereotaxic brain injection (0.5mg). Behavioral tests (elevated plus maze, open field, sucrose preference) and sperm analysis (morphology, DNA damage, viability).

What this study cannot tell us

Very small sample (5 per group). Stereotaxic brain injection is not clinically practical. Cannabis delivery via smoking machine may not replicate human use patterns. Short intervention period. Male rats only.

How to read the evidence

Novel finding with dual behavioral and reproductive outcomes, but very small sample and invasive delivery method limit translation.

When this study was published

2025 animal study exploring GDNF as a dual-target therapy for cannabis addiction and fertility.

The bigger picture

The connection between brain GDNF levels and both addiction behavior and fertility opens a novel research avenue. If these findings translate, GDNF-targeted therapies could address two consequences of cannabis addiction simultaneously.

Questions still open

  • Could peripheral GDNF administration achieve similar effects?
  • Are these findings relevant to human cannabis users with fertility concerns?

Common questions

Does cannabis affect male fertility?
In this rat study, cannabis exposure significantly reduced germ cells, testis size, and sperm quality, consistent with prior evidence of cannabis-related male fertility impairment.
Can the fertility damage from cannabis be reversed?
GDNF treatment reversed some damage (sperm morphology, DNA damage, viability) but not all (testis size, germ cell counts), suggesting partial reversibility.

Read the original research

Assessment of addiction behavior and spermatogenesis in glial cell line-derived neurotrophic factor-treated cannabis-addicted rats: An experimental study.

International journal of reproductive biomedicine, 23(2), 153-170

Citation

Laleh, Rozhina; Nasrabadi, Mitra Heydari; Khodarahmi, Parvin; Soltani, Jamshid. (2025). Assessment of addiction behavior and spermatogenesis in glial cell line-derived neurotrophic factor-treated cannabis-addicted rats: An experimental study.. International journal of reproductive biomedicine, 23(2), 153-170. https://doi.org/10.18502/ijrm.v23i2.18487

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