Effect of intrathecal γ-aminobutyric acid transporter-1 siRNA on neuropathic pain in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of intrathecal γ-aminobutyric acid transporter-1 ( GAT-1 )small interfering RNA (siRNA) on neuropathic pain in rats. Methods Male SD rats weighing 200-250 g were studied. The experiment was performed in 3 parts. Part Ⅰ Twenty rats were randomly divided into 5 groups ( n =4 each): GAT-1 siRNA-1 group, GAT-1 siRNA-2 group, GAT-1 siRNA-3 group, negative control siRNA group and DEPC treatment group. Two days after ligation of sciatic nerve, intrathecal siRNA 2 μg or equal volume of DF-PC was injected once a day for 3 consecutive days. The rats were killed and the lumbar segment of the spinal cord was removed at 2nd day after the last intrathecal injection for determination of the expression of GAT-1 in the spinal dorsal horn by Western Blot. Part Ⅱ Thirty rats were randomly divided into 3 groups ( n = 10 each): GAT-1 siRNA-3 + lipo2000 group, GAT-1 siRNA-3 mismatch siRNA + lipo2000 group, and DEPC treatment + lipo2000group. Paw-withdrawl threshold (PWT) to thermal and mechanical stimulation was measured before ligation of sciatic nerve, 3 days after ligation of sciatic nerve and at 1, 3, 5, 7 and 10 days after consecutive administration for 3 days. Part Ⅲ Eighty-four rats were randomly divided into 3 groups as described in Part Ⅱ ( n = 28 each). Four rats were killed at each time point and the lumbar segment of the spinal cord was removed for determination of the expression of GAT-1 in the spinal dorsal horn by Western blot. Results PWT to thermal and mechanical stimulation was significantly inreased and the GAT-1 expression was down-regulated after the injection of GAT-1 siRNA.Conclusion Intrathecal GAT-1 siRNA can reduce the neuropathic pain by inhibiton of up-regulation of the GAT-1 expression in the spinal dorsal horn in rats.