中文摘要：

目的研究米诺环素缓解大鼠甲醛溶液炎性痛的脊髓机制。方法行为学实验：3～5周龄雄性SD大鼠随机分为4组：对照组、模型组、溶媒对照组及米诺环素组。模型组、溶媒对照组及米诺环素组大鼠于右后足背皮下注射10％中性甲醛溶液，对照组大鼠右后足背皮下注射生理盐水，其中溶媒对照组和米诺环素组在甲醛溶液注射前1h分别腹腔注射生理盐水和米诺环素，观察各组大鼠缩足和舔爪等炎性痛行为。电生理实验：选取同上SD大鼠，制作离体脊髓纵切片。采用全细胞膜片钳技术记录米诺环素对脊髓背角胶状质（SG）神经元的自发性抑制性突触后电流（sIPSCs）的作用。结果与对照组相比，模型组缩足和舔爪时间显著增加；与溶媒对照组比较，米诺环素组缩足和舔爪时间显著减少。对照组和米诺环素组sIPSCs的频率分别为（2．5±0．3）Hz和（5．2±0．6）Hz，米诺环素可显著增加SG神经元sIPSCs的频率（t=9．32，P〈0．05），而对其幅度元明显影响（t=1．54，P〉0．05）。去除细胞外液中的钙离子后，米诺环素用药前后sIPSCs的频率分别为（0．9±0．1）Hz与（0．9±0．1）Hz，振幅分别为（18．2±0．7）pA与（18．5±0．6）pA，差异均无统计学意义（t=0．32、0．82，均P〉0．05）。在细胞外液中加入谷氨酸受体阻滞剂6-氰基-7-硝基喹喔啉-2，3-二酮（CNQX）和D-α-氨基磷酸基戊酸（APV）后，米诺环素仍可增加sIPSCs的频率，分别为（2．0±0．1）Hz与（4．3±0．4）Hz，差异有统计学意义（t=13．51，P〈0．05）。在细胞外液中加入电压门控钠通道阻滞剂河豚毒素（TTX）后，米诺环素仍可增加IPSCs的频率，分别为（2．2±0．2）Hz与（5．2±0．5）Hz，差异有统计学意义（t=8．67，P〈0．05）。结论米诺环素可缓解甲醛溶液诱导的炎性痛，这一效应与其增加脊髓背角SG神经元的抑制性?

英文摘要：

Objective To investigate the spinal analgesic mechanism of minocycline in formalin- induced inflammatory pain. Methods Behavioral test： Male Sprague-Dawley rats （3-5-week old） were randomly assigned into four groups： control, model, vehicle-controlled and minocycline group. Ten percent neutral formalin was injected subcutaneously into the right hind paw dorsum of the rats in model, vehicle- controlled and minocycline group. Normal saline was injected subcutaneously into the right hind paw dorsum of the rats in control group. Before 1 h of formalin injection, the rats in vehicle-controlled and minocycline group received intraperitoneal injection of saline and minocycline, respectively. Licking and lifting time was observed as the behavior results of inflammatory pain. Electrophysiologic experiment： In vitro spinal cord parasagittal slices were prepared from the same rats as above. The effect of minocycline on spontaneous inhibitory postsynaptic currents（sIPSCs） of substantia gelatinosa （SG） neurons was observed using whole- cell patch-clamp technique. Results Compared with the control group, the licking and lifting time in the model group was significantly increased. Compared with the vehicle-controlled group, the licking and lifting time in the minocycline group was significantly decreased. Minocycline significantly increased the frequency （t =9. 32, P 〈0. 05）but not the amplitude（t = 1.54, P 〉0. 05） of sIPSCs of SG neurons, the frequency of sIPSCs of control and minocycline group were （ 2. 5 ± 0. 3 ） Hz and （ 5.2 ± 0. 6 ） Hz, respectively. When calcium was removed from the extracellular solution, the frequency before and after minocycline perfusion were （0. 9 ± 0. 1 ）Hz and （0. 9 ± 0. 1 ）Hz, respectively, the amplitude before and after minocycline perfusion were （ 18.2 ± 0. 7 ） pA and （ 18.5 ± 0. 6 ） pA, respectively, the difference of frequency or amplitude was not statistically significant （ t = 0. 32,0. 82, all P 〉 0. 05 ） . However, minocyclin