A total of 30 female Sprague-Dawley rats (age, 2 months; weight, 180–220 g) were purchased from The Experimental Animal Center of Nantong University (Nantong, China) and subjected to sciatic nerve crush injury as previously described (11 (link)). Rats were anaesthetized by injecting 2 ml/kg Equithesin (Sigma-Aldrich; Merck KGaA, Darmstadt, Germany), as previously described (12 (link)), corresponding to 17 mg/kg sodium pentobarbital, 42 mg/kg magnesium sulfate and 85 mg/kg trichloroacetaldehyde monohydrate) (11 (link),16 (link)). Anesthesia was assessed by loss of pedal reflexes. Rat left sciatic nerves were crushed with forceps for 10 sec, three times. To minimize the discomfort and possible painful mechanical stimulation, the rats were housed in large cages with sawdust bedding post-surgery and maintained in a controlled environment under constant temperature of 25°C and relative humidity of 40–70%, with a 12 h light/dark cycle and free access to food and water. Rats were sacrificed 24 h, 4 days, or 1, 2, 3, 4 or 8 weeks following surgery. Gastrocnemius muscles from the left (injured) side and the right (uninjured) side were collected. Control rats were anesthetized without sciatic nerve crushing (sham surgery). All animal procedures were ethically approved by The Administration Committee of Experimental Animals of The Jiangsu Province (Jiangsu, China).