Background: This study aimed to investigate the possible therapeutic benefits of Huperzine A on autistic behaviours and histological alterations in the cerebellum of a rat model of autism.

Methods: This study utilized 30 male neonatal rat pups (10 per group) to investigate the effects of valproic acid on the rat cerebellum. Pregnant Wistar female rats received valproic acid (VPA) on the 12.5th gestation day, and their pups were administered VPA on postnatal day 14, while the control group received saline on the corresponding days. It was determined that the experimental group received Huperzine A (0.80 μmol/kg) administered via intraperitoneal injection from postnatal day 14 to postnatal day 40. The elevated plus-maze, rotarod, and Morris water maze assessments were employed to investigate autism-like behaviours. Furthermore, on postnatal day 41, the brains of all puppies were excised and prepared for histological examination, and hippocampus homogenates were obtained for the quantification of acetylcholinesterase (AChE) in cerebellar tissue homogenates.

Results: Huperzine A (HupA) treatment reduced anxiety in VPA-induced autism spectrum disorder (ASD) rats. The elevated plus-maze revealed that, at postnatal day (PND) 40, significant decreases in open-arm entries and time were observed (p < 0.0001). Non-significant effects at PND 21 (p = 0.99, p = 0.98). Moreover, HupA improved memory in ASD rats. Morris water maze test revealed that escape latency significantly decreased (p < 0.0001) at PND 39. Memory retrieval improved with HupA (p < 0.0001). Non-significant escape delay increased at PND 38 (p = 0.24). HupA also improved motor coordination in ASD rats. Rotarod test showed a significant endurance time decrease in ASD rats (p < 0.0001). HupA mitigated effects at PND 25 and PND 26 (p < 0.0001) but not at PND 24 (p = 0.10). HupA increased AChE levels in ASD rats. Group II had significantly lower AChE (p < 0.0001) than controls. Group III showed a non-significant increase versus controls (p = 0.0698). Huperzine A treatment considerably improved the cerebellar histological and immunohistochemical structural alterations.

Conclusions: These findings stress the critical impact of Huperzine A on neurobehavioral alterations, acetylcholinesterase, and cerebellar histological alterations in ASDs.