Ciproxifan improves cholinergic transmission, attenuates neuroinflammation and oxidative stress but does not reduce amyloid level in transgenic mice

Abstract

Aim The present study is aimed to investigate the ability of ciproxifan, a histamine H3 receptor antagonist to inhibit β-amyloid (Aβ)-induced neurotoxicity in SK-N-SH cells and APP transgenic mouse model. Materials and methods In vitro studies was designed to evaluate the neuroprotective effects of ciproxifan in Aβ25–35 - induced SK-N-SH cells. For the in vivo study, ciproxifan (1 and 3 mg/kg, i.p.) was administrated to transgenic mice for 15 days and behaviour was assessed using the radial arm maze (RAM). Brain tissues were collected to measure Aβ levels (Aβ1–40 and Aβ1–42), acetylcholine (ACh), acetylcholinesterase (AChE), nitric oxide (NO), lipid peroxidation (LPO), antioxidant activities, cyclooxygenases (COX) and cytokines (IL-1α, IL-1β and IL-6), while plasma was collected to measure TGF-1β. Results The in vitro studies demonstrated neuroprotective effect of ciproxifan by increasing cell viability and inhibiting reactive oxygen species (ROS) in Aβ25–35-induced SK-N-SH cells. Ciproxifan significantly improved the behavioural parameters in RAM. Ciproxifan however, did not alter the Aβ levels in APP transgenic mice. Ciproxifan increased ACh and showed anti-oxidant properties by reducing NO and LPO levels as well as enhancing antioxidant levels. The neuroinflammatory analysis showed that ciproxifan reduced both COX-1 and COX-2 activities, decreased the level of pro-inflammatory cytokines IL-1α, IL-1β and IL-6 and increased the level of anti-inflammatory cytokine TGF-1β. Conclusion This present study provides scientific evidence of the use of ciproxifan via antioxidant and cholinergic pathways in the management of AD.