2.2. Rat CCI model establishment

Adult female Sprague Dawley (SD) rats (weighing 180‐210 g) were purchased from Shanghai, Lab. Animal Research Center. All rats were housed in cages with a constant temperature of 25°C.

The CCI rat model was developed according to previously described methods. 19 Briefly, the rats were anaesthetized by intraperitoneal injections of 40 mg/kg pentobarbital sodium. The sciatic nerves on both sides of the rats were exposed and isolated from the surrounding tissues. The posterior medial sciatic nerve of the left femur was exposed, set free for 5‐6 mm before bifurcating and ligated 4 times within l mm. After the surgery, the incision was sutured layer by layer. Rats in the sham group were subjected to exposure and isolation of the sciatic nerve without ligation. There were 18 rats in the sham group and CCI group (without infection with lentivirus), respectively. The rats developed with CCI were then infected with lentiviruses expressing miR‐101, miR‐101‐inhibitor, MKP‐1, negative control (NC), namely, LV‐miR‐101, LV‐miR‐101‐inhibitor, LV‐MKP‐1 and LV‐NC, with 9 rats in each group. The remaining rats developed with CCI were treated with MKP‐1 inhibitor, RO318220 or infected with LV‐miR‐101 and LV‐MKP‐1 or LV‐NC in combination, with 9 rats in each group. Three rats were randomly selected and euthanized at each time when the spinal cord tissue was harvested, and six randomly selected rats were used for behavioural tests. Next, L4‐L6 spinal cord segment was harvested on days 0, 3, 7, 14 and 21 after the CCI induction surgery.