Alzheimer’s disease (AD) is the most common form of dementia, but there is still no available treatment. Δ9-tetrahydrocannabinol (THC) is emerging as a promising therapeutic agent. Using THC in conventional high doses may have deleterious effects. Therefore, we propose to use an ultra-low dose of THC (ULD-THC). We previously published that a single injection of ULD-THC ameliorated cognitive functioning in several models of brain injuries as well as in naturally aging mice. Here, 5xFAD AD model mice received a single treatment of ULD-THC (0.002 mg/kg) after disease onset and were examined in two separate experiments for cognitive functions, neurotropic, and inflammatory factors in the hippocampus. We show that a single injection of ULD-THC alleviated cognitive impairments in 6- and 12-month-old 5xFAD mice. On the biochemical level, our results indicate an imbalance between the truncated TrkB receptor isoform and the full receptor, with AD mice showing a greater tendency to express the truncated receptor, and ULD-THC improved this imbalance. We also investigated the expression of three AD-related inflammatory markers and found an ameliorating effect of ULD-THC. The current research demonstrates for the first time the beneficial effects of a single ultra-low dose of THC in a mouse model of AD after disease onset.

Maternal obesity in pregnancy and lactation is linked to metabolic disturbances and neurodevelopmental problems in offspring, increasing the risk of psychiatric disorders in adulthood. We proposed that maternal N-acetyl cysteine (NAC) supplementation during lactation, a critical period for neurodevelopment, potentially protects offspring from developing cognitive impairment in adulthood. Fifteen young female ICR mice were randomly allocated to different experimental groups: high-fat diet (HFD; 60.3% fat before mating, during pregnancy and lactation), HFD-NAC of 300 mg/kg/day during lactation, CD (high-fat diet before mating, during pregnancy, and regular chow control diet of 8.2% fat during lactation), CD-NAC of 300 mg/kg/day during lactation and control group consuming regular chow diet. The serum inflammatory markers of the offspring were evaluated post-weaning, while metabolic markers, microglial density, and cognitive performance were assessed in adulthood using the novel Object Recognition and Morris Water Maze tests. Our results demonstrate maternal obesity during gestation and lactation increased body weight, hepatic steatosis, and microglial cell density in the dentate gyrus (DG) and cortex. Furthermore, these offspring exhibited reduced spatial learning abilities in adulthood, regardless of sex. However, maternal NAC administration during lactation and maternal diet intervention significantly reduced brain microglial density and improved both male and female offspring metabolic profiles. More importantly, NAC supplementation during lactation, regardless of maternal diet, enhanced male offspring's learning ability in adulthood. Our findings indicate that administering NAC to obese mothers during the critical lactation period may offer protection against metabolic disturbances and cognitive deficits in adult offspring previously exposed to maternal obesity.