Two months of daily THC caused retinal damage in mice through inflammation and oxidative stress

THC at 1-2 mg/kg daily for 2 months caused functional loss on electroretinography, increased photoreceptor cell apoptosis, elevated inflammatory markers (TNF-alpha, IL-1beta, IL-6), and increased oxidative stress markers in retinal tissue. Higher doses produced more severe effects.

BALB/c mice received daily intraperitoneal THC (1 or 2 mg/kg) or vehicle for 2 months. Retinal function assessed by electroretinography. Retinal morphology by H&E staining. Apoptosis by TUNEL assay. Inflammation and oxidative stress by ELISA. Gene and protein expression by RT-PCR and Western blot.

While cannabis effects on the brain are widely studied, retinal effects are poorly understood. This study raises the possibility that chronic THC use could affect vision through inflammatory and oxidative damage to the retina.

Cannabinoid receptors are present in the retina, and this study suggests chronic THC exposure could have ocular consequences. As cannabis use becomes more common, understanding potential visual effects is important for public health.

Animal study using intraperitoneal injection, which differs from human routes of administration. BALB/c mice may be particularly susceptible to retinal damage. Two months in mice may not correspond to equivalent human exposure duration. No behavioral visual assessment was performed.