<p style="text-align: center;">LIU Kun¹, ZHI Mujun², ZHENG Zhouli³, HE Xun¹, SUN Guang², ZHANG Meng⁴, GAO Xinyan¹, ZHU Bing¹</p><p style="text-align: center;">(1 Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of&nbsp; Chinese Medical Sciences, Beijing, People’s Republic of China; 2 College of Acupuncture and Moxibustion, Changchun University of Chinese Medicine, Changchun, People’s Republic of China; 3 College of Acupuncture and Moxibution, Shaanxi University of Chinese Medicine, People’s Republic of China; 4 Department of&nbsp; &nbsp;Chinese Medicine, Dongli Hospital of Traditional&nbsp;&nbsp;</p><p style="text-align: center;">Chinese Medicine, Tianjin, People’s Republic of China)</p><p style="text-align: justify;"><strong>Abstract</strong>: <strong>Purpose</strong>: To validate and explore the application of a rat model of chronic constriction injury&nbsp; to the partial sciatic nerve in investigation of acupuncture analgesia.&nbsp; Methods:&nbsp; Chronic constriction injury of the sciatic nerve (CCI) and chronic constriction&nbsp; injury of the partial sciatic nerve (CCIp) models were generated by ligating either the sciatic&nbsp; nerve trunk or its branches in rats.&nbsp; Both&nbsp; models&nbsp; were&nbsp; evaluated&nbsp; via&nbsp; paw&nbsp; mechanical&nbsp; withdrawal&nbsp; latency&nbsp; (PMWL),&nbsp; paw mechanical withdrawal threshold (PMWT), nociceptive reflex-induced&nbsp; electromyogram (C-fiber reflex&nbsp; EMG),&nbsp; and&nbsp; dorsal&nbsp; root&nbsp; ganglion&nbsp; immunohistochemistry.&nbsp; Electroacupuncture&nbsp; (EA)&nbsp; was performed&nbsp; at&nbsp; GB30&nbsp; to&nbsp; study&nbsp; the&nbsp; analgesic&nbsp; effects&nbsp; on&nbsp; neuropathic&nbsp; pain&nbsp; and&nbsp; the&nbsp; underlying mechanisms.&nbsp; <strong>Results</strong>:&nbsp; Following ligation of the common peroneal and tibial nerves, CCIp rats exhibited&nbsp; hindlimb dysfunction, hind paw shrinkage and lameness, mirroring those of CCI rats (generated by ligating the sciatic nerve trunk). Compared to presurgery measurements, CCIp and CCI modeling significantly decreased the PMWL and PMWT. EA at GB30 increased the PMWL and&nbsp; PMWT&nbsp; in&nbsp; both&nbsp; CCI&nbsp; and&nbsp; CCIp&nbsp; rats.&nbsp; Calcitonin&nbsp; gene-related&nbsp; polypeptide&nbsp; and&nbsp; substance&nbsp; expressions were apparently increased in both CCI and CCIp groups, but were not different from each other. The C-fiber reflex EMG of the biceps femoris was preserved in CCIp rats, but it could not&nbsp; be&nbsp; recorded&nbsp; in&nbsp; CCI&nbsp; rats&nbsp; on&nbsp; the&nbsp; 5th&nbsp; day&nbsp; after&nbsp; nerve&nbsp; ligation. The&nbsp; C-fiber&nbsp; reflex&nbsp; EMG&nbsp; was reduced at 0, 1, and 2 minutes after EA in CCIp rats, but only at 0 and 1 minute after EA&nbsp; in normal rats.&nbsp; <strong>Conclusion</strong>: The CCIp model is better than the CCI model for studying acupuncture analgesiaon chronic neuropathic pain and the underlying mechanisms.&nbsp;</p><p><strong>Key words</strong>: neuropathic pain, chronic constriction injury, acupuncture, analgesia, C-fiber reflex</p>