Role of NDRG2 in the dorsal horn of the spinal cord in rats with spinal nerve ligation of neuropathic pain / 临床麻醉学杂志

ABSTRACT

Objective To investigate the effect of NDRG2 on neuropathic pain model rats with spinal cord ligation(SNL)in the dorsal horn of the spinal cordby using intrathecal NDRG2 adenovirus (AD-Ndrg2-RNAi).Methods Forty-two male SD rats weighing 180-230 g were randomly divided into sham operation group (n=6)and SNL group (n=3 6).SNL group underwent lumbar spinal dor-sal ligation.The sham operation group only exposed the spinal nerve without ligation.The mechanical withdraw threshold (MWT)and thermal withdrawlantency (TWL)were measured at 1 d before op-eration and at 1,3,7,10,14 and 21 d after operation.After the behavioral testing,the rats in SNL group were sacrificed and the lumber segment of the spinal cord was removed to test theprotein and mRNA level of NDRG2.Another forty-eight male SD rats were randomly divided into 4 groups after intrathecal catheterization (n=12)group sham operation with saline (group CS);group sham oper-ation with adenovirus (group CA);group SNL with saline (group SS);group SNL with adenovirus(group SA).The rats in groups CS and SS were treated with intrathecal injection of normal saline 10 μl on the third day after operation,while groups CA and SA received the single injection titer of 2× 109PFU/ml of AD-Ndrg2-RNAi on the same day.The rat plantar MWT and TWL were measured at 1 d before SNL and at 1,3,7 and 10 d after SNL.The rats were sacrificed after the lastbehavioral test.Lumbar enlargement of the spinal cord was removed to test the level of NDRG2 and GFAP pro-tein.The expression of NDRG2 mRNA was detected by real-time fluorescence quantitative PCR. Results Compared with sham group,the MWT and TWL was significantly decreased and reduced in SNL group 1,3,7,10,14,21 d and 3,7,10,14,21 d after surgery respectively(P<0.01).Com-pared with 1 d before surgery,protein content and mRNA expression of NDRG2 in the spinal dorsal horn of the SNL group were significantly decreased 1 d after surgery,and they were significantly in-creased on the 7,10,14,and 21 d after operation(P<0.01).Compared with group CS,the MWT and TWL were significantly decreased and reduced in group SS and group SA 1,3,7 and 10 d after surgery(P<0.05).MWT and TWL on 7 and 10 d were increased significantly in group SA (P<0.05)compared with group SS.Compared with group CS,protein content and mRNA expression of NDRG2 in the spinal dorsal horn of group CA were significantly decreased,and increased significantly in group SS 10 d after surgery(P<0.05).Compared with group SS,protein content and mRNA ex-pression of NDRG2 in the spinal dorsal horn of group SA were significantly decreased.Compared with group CS,the protein content of GFAP in spinal dorsal horn of group CA,group SS and group SA were increased significantly 10 d after surgery (P<0.05).Conclusion Intrathecal injection of AD-Ndrg2-RNAi significantly inhibits neuropathic pain caused by spinal cord ligation in rats,suggesting that NDRG2 in astrocytes is involved in the development and progression of neuropathic pain.