芦荟苷预处理对大鼠脊髓缺血／再灌注损伤保护作用机制的实验研究

Experimental study on protective mechanism of Barbaloin pretreatment on spinal cord ischemic/reperfusion injury in rats

目的探讨芦荟苷对大鼠脊髓缺血／再灌注（I／R）损伤可能的保护机制。方法将96只健康雄性SD大鼠按随机数字表法均分为假手术组（Sham组）、芦荟苷组（Bar组）、I／R组以及I／R＋Bar组。采用无创伤动脉夹夹闭腹主动脉的方法复制大鼠脊髓I／R模型；Sham组仅开腹暴露腹主动脉，而不夹闭血管；I／R＋Bar组于制模前30d灌胃芦荟苷30mg·kg^-1·d^-1，然后开腹夹闭血管造成脊髓缺血45min后松开动脉夹再灌注24h；Bar组仅给予芦荟苷30mg·kg^-1·d。灌胃30d，然后开腹而不夹闭血管；I／R组仅开腹行I／R；Sham组和I／R组不预处理给药，分别灌胃等量生理盐水。对各组大鼠进行Basso、Beattie和Bresnahan（BBB）神经功能评分后处死取脊髓组织标本，检测各组脊髓组织丙二醛（MDA）、超氧化物歧化酶（SOD）的活性；采用酶联免疫吸附试验（ELISA）检测脊髓组织肿瘤坏死因子-α（TNF—α）和白细胞介素-1β（IL-1β）的含量。结果与Sham组比较，I／R组和I／R＋Bar组术后各时间点BBB神经功能评分、SOD均明显降低，MDA、TNF-α、IL-1β均明显升高（均P〈0．05），术后6h即表现出统计学差异，但I／R＋Bar组上述指标的变化均明显优于I／R组[术后6h：BBB评分（分）：4．8±0．8、2．8±0．5比21．0±0．0，SOD（U／mg）：215．41±16．62、152．19±12．36比268．43±18．12，MDA（mmol／mg）：5．12±0．79、8．56±0．83比2．56±0．65，TNF—α（pg／mg）：248．39±12．95、527．54±12．43比148．73±11．25，IL-1β（pg／mg）：85．47±6．53、139．42±8．61比41．92±1．75，均P〈0．05]。结论芦荟苷预处理可通过抑制大鼠脊髓I／R损伤导致的过度氧化应激及炎症反应，从而发挥保护作用机制。

Objective To investigate the possible protective mechanism of Barbaloin （Bar） pretreatment on spinal cord ischemia/reperfusion （I/R） injury in rats. Methods According to random number table method, 96 healthy male Sprague-Dawley （SD） rats were divided into sham operation group （Sham group）, Bar group, I/R group and I/R＋Bar group. The rat spinal cord I/R model was replicated by non-invasive clamping of the abdominal aorta; in the Sham group, only was the abdominal aorta exposed without vascular occlusion; in the I/R＋Bar group, before modeling, Bar （30 mg·kg^-1·d^-1） was administered to rats as a pretreatment by gavage for 30 days and then after laparotomy, vascular clamping was carried out resulting in spinal cord ischemia for 45 minutes, immediately the clamping was taken away and reperfusion was performed for 24 hours; in the Bar group, Bar （30 mg＂ kg-1 ~ d-1） was intra-gastrically administrated to the rats for 30 days as a pretreatment and then laparotomy without vascular clamping was performed; in I/R group, only were laparotomy and I/R performed; in sham and I/R groups, instead of any pretreatment, the same amount of normal saline was injected, respectively. After Basso, Beattie and Bresnahan （BBB） neurological function scores in each group of rats were evaluated, the rats were sacrificed and spinal tissue samples were obtained in various groups, the activities of malondialdehyde （MDA） and snperoxide dismntase （SOD） in spinal cord tissues were detected; the contents of tumor necrosis factor-ct （TNF-α） and interleukin-1 β （IL-1β ） in spinal cord tissues were measured by enzyme-linked immunosorbent assay （ELISA） in the three groups. Results Compared with the Sham group, in the I/R group and the I/R＋Bar group, the BBB neurological scores and the levels of SOD were significantly decreased at different time points, and the levels of MDA, TNF- α, and IL-1 β were obviously increased （all P 〈 0.05）, at 6 hours after surgery, the statistical differences in above indicators were seen, and the differences in I/R＋Bar group were significantly better than those in I/R groupβ hours after surgery： BBB score was 4.8± 0.8, 2.8 ± 0.5 vs. 21.0 ± 0.0, SOD （U/mg）： 215.41 ± 16.62, 152.19±12.36 vs. 268.43±18.12, MDA （mmol/mg）： 5.12±0.79, 8.56＋0.83 vs. 2.56±0.65, TNF-α （pg/mg）： 248.39± 12.95, 527.54 ± 12.43 vs. 148.73± 11.25, IL-1β （pg/mg）： 85.47 ± 6.53, 139.42 ± 8.61 vs. 41.92 ± 1.75, all P 〈 0.05]. Conclusion Bar pretreatment can exert a protective effect by inhibiting the excessive oxidative stress and inflammatory response induced by spinal cord ischemia-reperfusion injury in rats.