Cobrotoxin mitigates neuroinflammation and cognitive impairment by suppressing CD8(+) T cell-microglia interactions in male 5 × FAD mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline accompanied by chronic neuroinflammation. Emerging evidence implicates T-cell infiltration and microglial activation as key immune events that accelerate AD pathology, yet therapeutic approaches targeting this neuroimmune interface remain scarce. Cobrotoxin (CTX), a short-chain neurotoxin derived from Naja atra venom, exhibits potent anti-inflammatory and immunomodulatory properties and is clinically approved in China for the treatment of chronic pain syndromes. Here, we investigated whether CTX could alleviate neuroinflammation and cognitive deficits in 5 × FAD mice, a transgenic model of AD. Intranasal CTX administration for nine weeks enhanced spatial learning and memory in the Morris water maze without altering amyloid-β burden. Flow cytometry and immunofluorescence revealed that CTX markedly reduced brain-infiltrating CD8