关节炎慢性吗啡耐受大鼠脊髓背角谷氨酸转运体3型的表达

目的观察谷氨酸转运体3型(EAAT3)在关节炎慢性吗啡耐受大鼠脊髓背角表达的变化。方法36只健康雄性SD大鼠随机分为六组,每组6只,行鞘内置管。其中的四组制成佐剂性关节炎模型,分别经鞘内给予生理盐水(A组)、吗啡10μg/kg(B组)、吗啡20μg/kg(C组)、吗啡10μg/kg加纳洛酮10μg/kg(D组);另外两组非致炎大鼠分别经鞘内给予生理盐水(E组)、吗啡20μg/kg(F组)。各组给药均为每日2次,连续7d。动态检测大鼠50%缩爪阈值,以免疫组化方法检测脊髓背角EAAT3表达。结果B、C组关节炎大鼠在鞘内给予吗啡第7天形成较稳定的吗啡耐受,其脊髓背角EAAT3表达下降。结论脊髓EAAT3可能参与炎性痛大鼠慢性吗啡耐受的形成机制。

Expression of EAAT3 in spinal cord dorsal horn of arthritis rats with chronic morphine tolerance

Objective To study the expression of EAAT3 in the spinal cord dorsal horn of arthritis rats with chronic morphine tolerance. Methods Thirty-six healthy male SD rats implanted intrathecal catheter were randomized into 6 groups with 6 rats each. The model of adjuvant-induced arthritis was established in 24 rats,which were intrathecally given normal saline (group A), morphine 10 μg/kg(group B), morphine 20μg/kg(group C), or morphine 10 μg/kg plus naloxone 10 μg/kg(group D). The rats in the other two groups without arthritis were administered intrathecally saline (group E) and morphine 20 μg/kg(group F), respectively. The drugs were administered twice daily for 7 days. Mechanical withdrawl threshold(MWT) of rats was examined to evaluate its behavior. Immaunohistochemistry was used to detect the expression of EAAT3 in the spinal cord dorsal horn. Results Morphine tolerance was formmed stably in groups of B and C on the 7_thday after morphine injection. The expression of GLAST in the spinal cord dorsal horn was downregulated. Conclusion Spinal EAAT3 may be involved in the development of morphine tolerance in rats with inflammatory pain.