Functional constipation （FC） is a clinically common functional bowel disorder characterized by a protracted course and associations with various chronic disorders and psychological abnormalities. Although not life-threatening， FC significantly impairs patients' quality of life. FC subtypes include slow-transit constipation （STC）， defecatory disorder （DD）， and normal-transit constipation （NTC）. The pathological mechanisms underlying FC have not been fully elucidated， and overall clinical efficacy remains unsatisfactory. Animal models of FC serve as essential tools for the study of disease mechanisms and the development of novel therapeutics. This article systematically reviews the current state of research on the animal models of FC and identifies that rodents， particularly rats and mice， are the most commonly used species. Dogs and pigs are also employed in complex intervention studies due to their physiological similarities to humans， though their use is limited by housing challenges and ethical considerations. Induction methods vary across different FC subtypes. STC models are primarily established with chemical agents such as loperamide or compound diphenoxylate. DD modeling often involves low-fiber diets combined with methylene blue injection or rectal narrowing. NTC modeling mainly relies on low-fiber dietary interventions. In addition， disease-syndrome combination models based on traditional Chinese medicine （TCM） theory have been developed， encompassing excess patterns such as heat accumulation， cold accumulation， and Qi stagnation， as well as deficiency patterns including Qi deficiency， blood deficiency， Yin deficiency， and Yang deficiency. These are achieved through an approach of disease model + syndrome induction， enabling the integration of mechanisms from both Western and TCM perspectives. Models are evaluated from two aspects： disease and syndrome manifestations （e.g.， colonic transit， secretory function， and TCM syndrome indicators such as mental state and body weight） and disease mechanisms （e.g.， enteric nervous system， interstitial cells of Cajal， smooth muscle cells， gut microbiota， and metabolites）. However， current research still faces challenges such as poor consistency in some models， non-specific interference in mechanism interpretation， insufficient studies on NTC， and lack of TCM tongue and pulse diagnosis in evaluation. Future efforts should focus on optimizing model stability and specificity to provide a more reliable experimental basis for investigating the pathological mechanisms of FC and developing therapeutic agents.

ObjectiveTo explore the effects of electroacupuncture at governor vessel or Jiaji acupoints on the activation of lumbar spinal cord neurons and the recovery of motor function in paralyzed hind limbs in rats with complete transection of spinal cord injury. MethodsTwenty adult female SD rats were selected. Among them， 15 rats underwent the complete transection of the 10th thoracic spinal cord and were randomly divided into the Control group， the electroacupuncture at governor vessel acupoints （GV） group and the electroacupuncture at Jiaji acupoints （JJ） group， with 5 rats in each group. The other 5 rats served as the Normal group. Electroacupuncture treatment was initiated 3 days after surgery in the GV and JJ groups and performed every other day. Basso-Beatti-Bresnahan （BBB） behavioral score was evaluated weekly. Eight weeks after the operation， cortical motor evoked potential （CMEP） detection was performed， followed by perfusion fixation， tissue harvest， frozen sectioning， and immunofluorescence staining experiments. Results① Both electroacupuncture treatments activated the expression of the excitatory marker c-Fos in L1 spinal cord neurons. The c-Fos⁺ activated neurons were mainly distributed in lamina Ⅳ， Ⅴ and Ⅶ of the L1 spinal cord， while no c-Fos⁺ neuron was observed in the Normal group and the Control group. The percentages of c-Fos⁺ neurons activated by electroacupuncture in the GV group and the JJ group were （10.23±0.15） % and （10.77±1.12） %， respectively， and there was no significant difference between the two electroacupuncture groups. ② vGluT1⁺ proprioceptive afferent nerve fibers were mainly distributed in the dorsal horn and lamina Ⅶ of intermediate zone of L1 spinal cord gray matter. In the dorsal horn of L1 spinal cord， the relative fluorescence intensity of vGluT1⁺ nerve fibers in the GV group and the JJ group were greater than that in the Control group， and that in the JJ group was greater than that in the GV group. In the lamina Ⅶ in intermediate zone of L1 spinal cord， where the central pattern generator （CPG） for hindlimb rhythmic movement is located， the relative fluorescence intensity of vGluT1⁺ nerve fibers in the GV group and the JJ group were significantly higher than that in the Control group， and the JJ group was also higher than the GV group； The lamina Ⅶ neurons innervated by vGluT1⁺ axon terminals were activated to express the excitatory marker c-Fos in the GV group and the JJ group. ③ The immunofluorescence staining results of acetylcholinesterase （ChAT） in the ventral horn of L4 spinal cord of each group showed that the number of surviving ChAT⁺ motor neurons in the GV group （19.1±3.4， P=0.000 2） and JJ group （19.0±2.9， P=0.000 2） were higher than that in the Control group （9.9±1.9）. ④ The quantitative analysis of the vGluT2⁺ excitatory axonal terminals， vGAT⁺ inhibitory axonal terminals， and the ratio of vGluT2⁺/vGAT⁺ axonal terminals ［reflecting the excitation/inhibition （E/I） balance of motor neurons］ innervating ChAT⁺ motor neurons in the ventral horn of the L4 spinal cord revealed that all three indices were significantly higher in the GV and JJ groups than in the Control group. Moreover， the E/I ratio of motor neurons in the two electroacupuncture groups gradually reached the same level as normal and showed no statistical difference from the Normal group. ⑤ The electrophysiological and behavioral detection results showed that compared with the Control group， the latencies of CMEP in the GV group and the JJ group shortened， while their amplitudes increased. The BBB score of paralyzed hindlimbs showed that after 8 weeks of treatment， the scores of both the GV group （4.25±1.26， P=0.023 4） and the JJ group （4.75±0.96， P=0.000 2） were higher than those of the Control group （1.80±1.30）， but there was no statistical difference between the two electroacupuncture groups. ConclusionElectroacupuncture at GV or JJ acupoints may promote the afferent of vGluT1⁺ proprioceptive nerve fibers into the spinal cord， indicating the possibility to activate CPG neurons in lamina Ⅶ of L1 spinal cord； facilitate the survival of motor neurons in the L4 spinal cord and restore their excitatory/inhibitory balance， improving the motor function of the paralyzed hindlimbs in rats.