海马注射白细胞介素-2对痛阈及甲醛引起的中脑导水管周围灰质和脊髓内P物质样免疫活性的影响(英文)

Effects of intra-hippocampal injection of interleukin-2 on pain threshold and formaldehyde-induced substance P-like immunoreactivity in periaqueductal gray and spinal cord

目的:观察海马内注射白细胞介素-2(IL-2)对痛阈、中脑导水管周围灰质(PAG)和脊髓内P物质(SP)的影响。方法:热痛测试法和免疫组化法。结果:海马内微量注射IL-2480U可使痛阈明显提高,高峰时比对照组增加93％±57％(P<0.01),足底注射甲醛引起双侧PAG SP-LI细胞减少(2.9±2.8 vs 22.1±0.7,12.3±2.0 vs 22.4±1.0,P<0.01)和脊髓同侧背角SP-LI增多(0.836±0.015 vs0.59±0.09,P<O.01),而海马内注射IL-2480U抑制足底注射甲醛在PAG(11.3±2.3 vs 2.9±2.8,16.9±3.4 vs 12.3±2.0,P<0.05)和脊髓(0.71±0.03 vs 0.836±0.015,P<0.01)对SP-LI的作用,腹腔注射促皮质素与海马内注射IL-2对抑制甲醛引起的PAG内SP-LI细胞减少的效应有协同作用。结论:海马内注射IL-2的镇痛作用与PAG的SP增多和脊髓SP的减少有关,而IL-2与促皮质素之间有协同作用。

AIM: To study the effects of intra-hippocampal injection of interleukin-2 (IL-2) on the substance P-like immunoreactivity (SP-LI) in both periaqueductal gray (PAG) and spinal cord, and on pain threshold in rats. METHODS: Immunohistochemistry technique was used and the paw withdrawal threshold to radiant heat was measured. RESULTS: Microinjection of hIL-2 480 U in hippocampus (Hip) increased the pain threshold (93 %±57 % , P < 0.01). Injection of formaldehyde (For) in one hindpaw decreased SP-LI neuron number on both sides of PAG (2.9± 2.8 vs 22.1 ±0.7, 12.3±2.0 vs 22.4 ± 1.0, P<0.01) and increased SP-LI in ipsilateral spinal cord (0.836 ± 0.015 vs 0.59±0.09, P<0.01). Microinjection of hIL-2 480 U in Hip inhibited the effects of For on the SP-LI on both sides of the PAG (11.3 ±2.3 vs 2.9± 2.8, 16.9±3.4 vs 12.3±2.0, P<0.05) and spinal cord (0.71±0.03 vs 0.836±0.015, P < 0.01). The combination of intraperitoneal injection of corticotropin and intra-hippocampal injection of IL-2 increased the number of SP-LI neurons in PAG furtherly as compared with IL-2 240 U alone (13.6±3.6 vs 7.6±4.3,P < 0.05). CONCLUSION: The analgesic effects of intra-hippocampal injection of IL-2 are mediated, possibly, via the increase of SP in PAG and the decrease of SP in the spinal cord. There is asynergetic relation between IL-2 and corticotropin.