消退素D1对大鼠烧伤后疼痛和脊髓胶质细胞活化的影响

Effect of resolvin D1 on burn injury - induced pain and spinal cord glial activation in rats

目的观察消退素D1（RvDl）对大鼠烧伤后疼痛及脊髓胶质细胞活化的影响。方法140～150g幼年大鼠随机分为4组：对照组、烧伤组（B组）、RvD1低剂量治疗组[R（S）组]、RvDl高剂量治疗组[R（L）组]。制备烧伤模型，R（s）组和R（L）组于烧伤前30min及烧伤后1—7d分别腹腔注射100、300ngRvDl50“l，2次／d。分别于烧伤前1d和烧伤后1、3、5、7、14d测定大鼠机械缩足反应阈（MWT）。于烧伤后7dMWT测定结束后处死3只大鼠，用荧光免疫组织化学检测脊髓小胶质细胞和星形胶质细胞标志物离子钙结合适配器分子-1（Iba-1）和胶质酸性纤维蛋白（GFAP）表达。结果与对侧比较，B组烧伤侧烧伤后各时点MWT[（4．4±2．6）、（2．9±1．7）、（3．0±1．8）、（2．4±1．5）、（4．0±2．4）g]降低（P〈0．05），脊髓Iba-1（24．7±2．8）和GFAP表达（324±27）上调（P〈0．05）；与B组比较，R（S）组[（8．9±2．1）、（7．6±2．5）、（7．5±3．0）、（7．6±3．1）、（6．6±3．0）g]、R（L）组[（13．4±2．3）、（12．0±1．8）、（12．9±2．1）、（11．9±2．3）、（11．1±2．7）g]烧伤俱0烧伤后各时点MWT升高（P〈0．05），R（L）组脊髓Iba-1（6．7±2．2）和GFAP表达（210±25）下调（P〈0．05）。结论RvD1可通过抑制烧伤引起的大鼠脊髓胶质细胞活化，减轻大鼠烧伤后疼痛。

Objective To evaluate the effect of resolvin D1 on burn injury - induced pain and spi- nal cord microglial and astroglial activation in rats. Methods Young male Sprague - Dawley rats, weighing 140- 150 g, were randomly divided into 4 groups： control group, burn group （group B）, small- dose RvD1 treatment group [ group R （S） ], large -dose RvD1 treatment group [ group R （L） ]. The anesthe- tized rats received burn injury on dorsal hind paw. Phosphate buffer （PBS） or RvD1 （ 100 ng or 300 ng in 50 μl PBS） intraperitoneally, 30 min before burn injury, was administered for 7 days, twice a day. The rats were tested for mechanical paw withdrawal threshold （MWT） 1 day before and 1,3, 5, 7 and 14 days after burn. Three rats in each group were sacrificed after measurement of MWT at 7th day postburn for detection of the expression of Iba - 1 （a specific marker of microglia ） and glial fibrillary acidic protein （GFAP） （a specific marker of astroglia） at the spinal dorsal horn by immunofluorescence. Results As compared with the contralateral side, MWT was significantly decreased after burn on the ipsilateral side of rats in group B[（4.4±2.6）, （2.9±1.7）, （3.0±1.8）, （2.4±1.5）, and （4.0±2.4） gl, and the spinal dorsal horn expression of Iba - 1 （24. 7 ±2. 8） and GFAP （324 ±27） on the ipsilateral side of rats in group B was significantly increased. In the rats receiving 100 ng [ （8. 9 ±2. 1） , （7.6 ±2. 5） , （7.5 ± 3.0） ,（7.6±3. 1）, and （6.6 ±3.0） g] and 300 ng [（13.4 ±2.3）, （12.0 ± 1.8）, （12.9 ±2. 1）, （11.9 ± 2. 3 ）, and （11.1 ±2. 7） g] RvD1 intraperitoneally, mechanical allodynia was significantly attenuated. The administration of 300 ng RvD1 to the burned rats decreased the dorsal horn expression of Iba - 1 （6. 7 ± 2.2） and GFAP （210 ± 25 ） on the ipsilateral side on the day 7 after burn. Conclusion RvD1 may attenuate burn pain in rats via inhibiting microglial and astroglial activation.