糖尿病机械性痛模型大鼠P2X3受体的时空表达

Spatio-temporal expression of P2X3 receptor in rats with diabetic mechanical allodynia

目的：探讨糖尿病机械性痛（DMA）模型大鼠中P2X3受体（P2X3R）的时空表达变化。方法腹腔注射链脲菌素（ STZ）建立大鼠DMA模型。采用von Frey细丝法测定DMA大鼠机械性痛阈，在不同时间点取腰髓4～5（ L4～5）节段的脊髓背角（ SDH）和背根神经节（ DRG）以及足底皮肤，通过免疫荧光观察P2X3R阳性产物的表达变化。进一步Western blotting检测SDH和DRG中P2X3R蛋白的变化。结果与对照组（ CON组）相比，注射STZ 7d后大鼠机械性痛阈显著降低，在14d时达到最低并持续至28d（ P＜0．05）。免疫荧光和Western blotting结果均显示L4～5节段DRG中P2X3R表达在14d和21d时显著增多，与CON组相比差异有统计学意义（P＜0．05），28d时恢复至CON组水平；而在SDH及皮肤中，P2X3R表达上调出现在21d和28d（P＜0．05）。结论在STZ诱导的DMA大鼠机械性痛的不同时程中，DRG、SDH和皮肤中P2X3R的表达均呈现与痛敏变化几乎平行的变化趋势，但后两者比前者的变化在时间上略晚。这些结果说明P2X3R可能在DMA机械性痛敏的维持阶段起重要作用。

Objective To investigate the spatio-temporal expression of P2X3 receptor （ P2X3R） in rats with diabetic mechanical allodynia （ DMA ） .Methods DMA model in rats was induced by intraperitoneal injection of streptozocin （ STZ） .The von Frey filaments were applied to identify the changes of the paw withdrawal threshold （ PWT） in DMA rats.Immunofluorescence was employed to detect the spatio-temporal expression of P2X3R in the spinal dorsal horn （SDH）, dorsal root ganglion （DRG） and hind paw skin on different time points after intraperitoneal injection of STZ , respectively.The protein expression of P2X3R in SDH and DRG was further semi-quantitatively analyzed by Western blotting.Results Compared with control group , intraperitoneal injection STZ induced significant mechanical allodynia indicated by the reduced PWT from 7 days, and which reached the peak on 14d and maintained to 28days （P＆lt;0.05）. The expression of P2X3R in DRG neurons was significantly increased on 14 days and 21 days （P＆lt;0.05）, while that in SDH and skin was markedly increased on 21 days and 28 days, compared with control group （P＆lt;0.05）.Conclusion With the progress of DMA, the expression of P2X3R was significantly increased in the SDH, DRG and skin, which was almost parallel with the mechanical allodynia , but the changes in SDH and skin were 1 week later than that in DRG .These results suggest that P2X3R may play a key role in the maintenance of the DMA .