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.

Objective To investigate the stimulating effect of exogenous hydrogen sulfide (H2S) on angiogenesis in glioblastoma (GBM). Methods Twenty adult Sprague-Dawley (SD) rats were randomly divided into two groups, glioma group (C6 glioma cell intracerebral implantation, n=10) and glioma-H2S group (C6 glioma cell intracerebral implantation and sodium hydrosulfide (NaHS) intraperitoneal injection, n=10). The tumor-bearing rat model was established by intracerebral injection of rat C6 glioma cells. After one week, normal saline was injected in glioma group and NaHS was injected in glio-ma-H2S group. Food and water were freely available during all phases of the experiment. After three weeks, rats were decapi-tated and brains were removed. HE staining was performed to show tumor structure and intratumoral angiogenesis. The immu-nohistochemical analysis was used to detect the expressions of CD34 and MMP-2, respectively. The microvessel density (MVD) in GBM was also measured. Results HE staining showed that the implanted tumors were predominantly spheroid with clear border and no capsule could be detected. The neovascular proliferations were observed in tumors. There were high-er expressions of CD34 and MMP-2 in glioma-H2S group. The value of MVD was significantly higher in glioma-H2S group than that of glioma group (P＜0.01). Conclusion Exogenous H2S serves as a stimulator of angiogenesis in the development of rat GBM, which may be related with the increased MMP-2 expression promoted by H2S.