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Objective: To observe Intrathecal intermittent injection of 1% ropivacaine after 12h, 1 day, 3 days, 5 days, 7 days, 14 days, 28 days spinal cord oxidative stress, neurotoxicity and ERK1 expression, as well as the application of anti-oxidants' TEMPOL after the change in order to investigate the oxidative stress injury ropivacaine spinal cord nerve toxicity and its mechanism. Methods: 144 male SD rats using lumbar intrathecal catheter in the subarachnoid space built-into the PE10 catheter to the spinal cord lumbar enlargement, were randomly divided into four groups: S group (sham group), N (control group ), R group (ropivacaine group), T group (TEMPOL). S group only catheter administration; N group (control group) after injection the saline 0.12μL / g PE10 catheter intervals 1.5h 1, 8; R group (ropivacaine group) injected 1.0% Luo ropivacaine 0.12μL / g, an interval of 1.5 h 1, 8; T group (TEMPOL) first ropivacaine, the same way as the R group, last ropivacaine injection after 4h, 8h 12h, 24h, 48h, 72h were injected TEMPOL5μL (380 nmol). Groups were observed 1d, 3d, 5d, 7d, 14d, 28d harvested after. S group is referred to as \The N group denoted as \R group is referred to as \The T group recorded as \1 day and before injection After injection ropivacaine 1.5 h, 1 day, 3 days, 5 days, 7 days, 14 days, 28 days was measured thermal stimulus back of the posterior limbs (n = 6) condensing threshold, mechanical stimulation retraction threshold. The rats were sacrificed and the lumbar enlargement of the spinal cord tissue, morphological changes in spinal cord tissue HE staining, TUNEL staining to detect apoptosis, immunohistochemical determination of ERK1 expression, MDA content and SOD activity detected ROS level. Results: 1.1% ropivacaine 1.5h rats after intermittent intrathecal injection of the posterior limbs of the pain threshold increased significantly compared with the N group and S group, and the highest value on the first day, after which the pain domain value decreased gradually, but still high N group and S group until day 28 pain domain back to the level of Group N (P lt; 0.05). Compared with the R group, T group significantly decreased pain threshold in 1-3 days subsequent point in time the pain domain values ??are lower than the R group (P lt; 0.05), no significant difference in the first 28 days. The The 2.S group and the group N HE staining spinal cord does not appear obvious pathological changes, R group in 1-3 days spinal cord neuronal degeneration and apoptosis, after damage sustained development of apoptotic cells gradually increased, even partial necrosis, up to 14 days mitigate lesions, decrease in apoptotic cells. Compared with the R group, T group early more the number of normal neurons, fewer apoptotic cells, individual cell necrosis, 14 days most of the nerve cells normally seen only a small number of apoptotic cells, the first 28 days of spinal cord nerve cells form the basic properly. Compared with the N group, R1, R3, R5 group and T1, T3, T5 group of TUNEL positive cells increased significantly, then gradually decreased compared with the R group but significantly more than in the N group (P lt; 0.05); , T3 was significantly reduced after the T group were less than the number of positive cells R group (P lt; 0.05). 4 compared with the N group, R1, R3 group and T1, T3 group ERK1 expression was significantly higher, and gradually reduce, but still significantly higher than in group N (P lt; 0.05) until 28 days after return to the level of group N (P gt; 0.05). Compared with R T3 group ERK1 expression significantly reduced the subsequent expression of the T group were less than the R group (P lt; 0.05), up to 14 days, with no significant difference (P gt expression R group; 0.05). Compared with the N group, R1, R3, R5 group and T1, T3, T5, T7 group MDA content increased significantly, then gradually decreased, but the R group is still significantly higher than in group N (P lt; 0.05). T3 group MDA decreased significantly, compared with R, R group (P lt; 0.05) were less than the content of each time point thereafter. Compared with the N group, R1, R3, R5 group and T1, T3, T5, T7 group activity of SOD increased, then gradually decreased, but still significantly higher than in group N (P lt; 0.05). Compared with R, the T3 set of total SOD activity was significantly higher after the vitality of each time point were higher than the R group (P lt; 0.05). Conclusion: 1. Continuous intrathecal injection of 1% ropivacaine ROS levels were significantly increased 12h after spinal cord of rats, rat pain domain value increased spinal cord neurons undergo apoptosis; application of antioxidants TEMPOL can improve spinal ropivacaine neurotoxicity, suggesting that oxidative stress is involved in the ropivacaine lead to formation and development of the rat spinal cord neurotoxic injury. Intermittent intrathecal injection of 1% ropivacaine 12h after the increase of the level of ROS may promote neuronal apoptosis in spinal ropivacaine neurotoxicity through activation of the ERK pathway.
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