Objective: To investigate the therapeutic effect of Jian-Pi-Bu-Shen decoction on motor and balance ability in AR2 mice with amyotrophic lateral sclerosis (ALS) and its mechanism.

Methods: The conditional ADAR2 (adenosine deaminase acting on RNA 2) gene knockout AR2 mouse model was established. Forty-eight AR2 mice with partial motor neuron function were selected and randomly divided into control group and Jian-Pi-Bu-Shen decoction groups (low, medium and high dose, respectively), with 12 mice in each group. The mice in the control group were not given interventions except normal diet. The mice in the low-, medium- and high-dose Jian-Pi-Bu-Shen decoction groups received 15 mg/kg, 30 mg/kg and 45 mg/kg of Jian-Pi-Bu-Shen decoction, respectively once a day for 9 months. The body weight, posture, activity and the survival of mice were observed every month. The blood routine and liver and kidney function of mice were measured every 3 months. Before the intervention and 1, 3 and 6 months after the intervention, the mice were tested by rotating fatigue test, climbing rod test, beam balance test and treadmill test. The number of neurons in the anterior horn of spinal cord with immunoreactivity and lack of immunoreactivity of ADAR2 were examined at different ages. After 1 and 3 months of intervention, the number of neurons in the anterior horn of spinal cord was detected.

Results: From the third month of intervention, the motor ability of mice in the four groups decreased in varying degrees. With the intervention, the motor and balance abilities of mice in each dose group of Jian-Pi-Bu-Shen decoction were improved compared with those in the control group. After 3 months of intervention, the results of rotating fatigue test, beam balance test and treadmill test in the medium-dose Jian-Pi-Bu-Shen decoction group were significantly better than those in the control group (P < 0.05). After 3 months of intervention, the number of neurons in the anterior horn of spinal cord with immunoreactivity and lack of immunoreactivity of ADAR2 began to decrease, which was consistent with the progression of ALS. After 1 month and 3 months of intervention, the number of neurons in the anterior horn of spinal cord in the medium-dose and high-dose Jian-Pi-Bu-Shen decoction groups was more than that in the control group. During the intervention, the liver and kidney functions of mice were normal.

Conclusion: Jian-Pi-Bu-Shen decoction (especially medium dose) can improve the motor and balance abilities of AR2 mice, which may be related to delaying the loss and degeneration of neurons in the anterior horn of spinal cord and reducing the ADAR2 immune response of AR2 mice.