THC Exposure During Adolescence Damaged Testicular Function in Mice More Than Adult Exposure

Adolescent THC exposure (postnatal days 30-43) decreased sperm numbers, increased seminiferous tubule degeneration, and impaired steroidogenesis with dysregulated expression of key enzymes (StAR protein and CYP17A1). Adult exposure (postnatal days 70-83) reduced testosterone levels but did not affect sperm production or tubule structure. Both CB1 and CB2 receptors were confirmed present in the testis.

C57BL/6N male mice received daily THC injections (5 mg/kg) or vehicle during either adolescence (PND 30-43) or adulthood (PND 70-83). Testes were harvested 27 days after the last injection. Assessments included sperm counts, testicular histology, testosterone levels, and expression of endocannabinoid system components and steroidogenic enzymes.

Cannabis use typically begins during adolescence, and this study provides biological evidence that the developing reproductive system may be more vulnerable to THC than the mature one, with effects persisting weeks after exposure stops.

This adds to evidence that adolescent biology responds differently to cannabinoids than adult biology. The finding that testicular damage persisted nearly a month after THC stopped suggests the effects may not be quickly reversible during development.

Mouse model may not directly translate to humans. The 5 mg/kg dose via injection does not mimic typical human consumption patterns. Only one dose level was tested. Long-term recovery beyond 27 days was not assessed.