Trifluoro-icaritin alleviates chronic inflammatory pain through α7nAChR-mediated suppression of HMGB1/NF-κB signaling in the spinal cord of rats

Brain Res Bull. 2022 Feb 21:S0361-9230(22)00053-3. doi: 10.1016/j.brainresbull.2022.02.014. Online ahead of print.ABSTRACTInflammatory pain is a chronic, persistent and serious disease that greatly impacts public health, which is often accompanied by allodynia, hyperalgesia, and spontaneous pain. It is evident that α7 nicotinic acetylcholine receptor (α7nAChR) plays a key role in cholinergic anti-inflammatory pathway and exhibits the inhibition of neuroinflammation in chronic pain. Trifluoro-icaritin (ICTF), a derivative of icaritin from the extract of a genus of Epimedium plant, is identified to possess profound anti-inflammatory activity. However, whether ICTF has anti-nociceptive effect on inflammatory pain and its potential mechanisms remain poorly elucidated. Intraperitoneal injection (i.p.) of ICTF to complete Freund's adjuvant (CFA)-induced inflammatory pain rats once daily for 21 consecutive days. Pain-related behaviors were evaluated with paw withdrawal threshold (PWT), paw withdrawal latency (PWL), and CatWalk gait analysis. Expression of pain-related signaling molecules in the spinal cord were detected using qRT-PCR, western blot assay, and immunofluorescence staining. This results showed that ICTF (3.0mg/kg, i.p.) effectively alleviated mechanical allodynia and thermal hyperalgesia not 0.3 and 1.0mg/kg in CFA rats. Subsequently, we further observed that ICTF (3.0mg/kg) dramatically decreased the mRNA and protein levels of HMGB1, NF-κB p65, and IL-1β but marke...
Source: Brain Research - Category: Neurology Authors: Source Type: research