Cannabinoid exposure during pregnancy: consequences for growth, memory and prefrontal cortex integrity in Wistar Rats

Abstract

Background and aim: The increasing use of cannabis among pregnant women raises concerns about its potential impact on prenatal development. Many pregnant women use cannabis for its anti-emetic or anti-nausea effects, often under the belief that it is safe during pregnancy. However, prenatal exposure to the primary cannabinoids, THC and CBD, may result in neurodevelopmental deficits in offspring. This study aimed to assess the effects of late prenatal cannabis exposure on neurodevelopment in Wistar rats.

Materials and methods: Twenty-four female Wistar rats (12 weeks old) were mated, and pregnancy was confirmed by the presence of spermatozoa in vaginal smears on day 1. The animals were divided into four groups: Control (Group A), Late CBD (Group B), Late THC (Group C), and Late THC/CBD (Group D), with six rats per group. From gestational days 15 to 19, Group A received olive oil, Group B received CBD (150mg/kg body weight), Group C received THC (150mg/kg body weight), and Group D received a combination of CBD and THC (150mg/kg body weight each) via oral administration. After birth, the pups were allowed to grow, and at week 7, the adolescent rats were subjected to neurobehavioral tests. Upon completion of behavioral assessments, the rats were euthanized, and their brains were dissected, fixed in 10% formal saline, and processed for histological analysis.

Results: The results showed a significant reduction in birth weight at postnatal day 1 (PND 1) in the CBD, THC, and THC/CBD groups, with an increased percentage of alternate arm return at p< 0.05, morphological changes in pyramidal cells in the prefrontal cortex, indicating impaired cognition.

Conclusion: These findings suggest that late prenatal exposure to cannabis, specifically THC and CBD, leads to low birth weight and cognitive impairments in offspring, particularly in the prefrontal cortex.