Journal of Pain Research (Apr 2021)
Curcumin Alleviates Chronic Pain and Improves Cognitive Impairment via Enhancing Hippocampal Neurogenesis in Sciatic Nerve Constriction Rats
Abstract
Jingyi Du,* Yifan Deng,* Zhuolin Qiu, Guoliang Sun, Yue Guo, Ziqing Hei, Xiang Li Department of Anesthesiology, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xiang LiDepartment of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Number 600, Tianhe Road, Guangzhou, 510630, People’s Republic of ChinaTel/ Fax +86 20 8525 3132Email [email protected]: Cognitive impairment is a complication that most frequently happens in patients with chronic neuropathic pain and has limited effective therapy. The aim of this study was to explore the effects of curcumin on the cognitive deficit in rats with peripheral nerve injury induced-neuropathic pain.Methods: The neuropathic pain rat model was constructed using chronic constriction injury (CCI). The curcumin (60 mg/kg) or vehicle was intraperitoneally administered once a day, beginning at 14th day after surgery and continued for 14 consecutive days. The nociceptive threshold tests were measured by paw mechanical withdraw threshold (PMWT) and paw thermal withdrawal latency (PTWL), while the spatial memory abilities were evaluated by the Morris water maze test. The mean counts of bromodeoxyuridine (Brdu)/neuronal nuclei (NeuN) as well as Brdu/doublecortin (DCX) co-labeled cells were used to evaluate neurogenesis in the dentate gyrus of hippocampus. The ultrastructure of the synapse in hippocampal region was visualized using transmission electron microscopy (TEM).Results: Increased PMWT and PTWL, as well as relieved memory deficits, were found in CCI rats under curcumin administration. Moreover, curcumin treatment increased the number of newly born immature (BrdU/NeuN) and newly generated mature neurons (BrdU/DCX). The TEM examination revealed increased PSD thickness and shorter active zone length as well as narrowed synaptic cleft width in the hippocampal region of CCI rats after curcumin injection.Conclusion: Curcumin can alleviate CCI induced nociceptive behaviors and memory deficit. This effect might be associated with hippocampal neurogenesis and synaptic plasticity improvements, which indicated curcumin as a potential strategy for the cognitive impairment restoration under prolonged neuropathic pain condition.Keywords: curcumin, peripheral nerve injury, cognitive impairment, hippocampus neurogenesis
