异丙酚对慢性神经痛大鼠脊髓诱导型一氧化氮合酶表达的影响

Effect of propofol the expression of inducible nitric oxide synthase in the spinal cord in rats with chronic neuropathic pain

目的 研究不同剂量异丙酚对慢性神经痛大鼠触诱发痛痛阈及其脊髓组织诱导型一氧化氮合酶(iNOS)mRNA的影响。方法 Wistar大鼠40只,随机分为四组,Ⅰ组为空白对照;Ⅱ、Ⅲ、Ⅳ组结扎左侧坐骨神经。术后第7天,Ⅰ、Ⅱ组腹腔注射生理盐水50 ml·kg-1,Ⅲ、Ⅳ组腹腔注射异丙酚50 ml·kg-1或75ml·kg-1,每天一次共6 d。在术后第6、10和12天,使用Von Frey法分别测定各组大鼠触诱发痛痛阈,比较不同剂量的异丙酚对大鼠痛阈的影响。术后第12天取L4-5和L5-6节段脊神经节和脊髓组织,采用半定量RT-PCR法,对各组大鼠脊髓组织iNOS mRNA表达进行检测。结果 术后第10和12天,Ⅲ、Ⅳ组大鼠双侧的痛阈值高于Ⅱ组(P<0.05);术后第12天,Ⅲ、Ⅳ组大鼠脊髓组织iNOS mRNA表达低于Ⅱ组(P<0.05)。结论 异丙酚通过抑制脊髓组织iNOS mRNA转录,降低其表达,而起到一定的抗伤害作用。

Objective To investigate the effects of propofol the expression of inducible nitric oxide synthase (iNOS) in the spinal cord in rats with chronic neuropathic pain. Methods Forty adult Wistar rats of both sexes weighing 200-220 g were used in this study. Chronic neuropathic pain was produced by loose ligatures placed on the left sciatic nerve. Propofol or normal saline (NS) was given intraperitoneally (i.p. ) once a day for 6 days, seven days after sciatic nerve ligation. The animals were randomly divided into 4 groups (n = 10) : group Ⅰreceived NS 50 ml·kg-1 i.p. but no sciatic nerve ligation; group Ⅱ received sciatic nerve ligation and NS 50 ml·kg-1 i.p. ; group Ⅲ and Ⅳ received sciatic nerve ligation and propofol 50ml·kg-1 (Ⅲ) or75ml·kg-1 (Ⅳ) i.p. . Withdrawal threshold of both hind paws to Von Frey filaments was measured on the 6th , 10th and 12th days after sciatic nerve ligation. The animals were then sacrificed and the lumbar segment (L4-5) of the spinal cord was removed for the detection of iNOS mRNA expression by RT-PCR technique on the 12th day. Results The withdrawal threshold to Von Frey filament of both hind paws was significantly higher on the 10th and 12th days in the two propofol groups (group Ⅲ and Ⅳ) than in group Ⅱ(P < 0.05) . The expression of iNOS mRNA in group Ⅲ and Ⅳ was significantly lower than that in group n (P < 0.05) . Conclusion The antinociceptive effect of propofol is closely related to its inhibitory action on expression of iNOS mRNA in the spinal cord.