脑室注射白介素-1β引起的热痛敏作用

实验在SD大鼠上应用脑室微量注射和辐射热测痛的方法,研究了脑内微量注射白介素－1β对大鼠痛阈的影响。实验大鼠分为给药组和对照组,在给药组大鼠脑室注射不同剂量的白介素－1β（5、50和500pg/kg),对照组大鼠脑室注射配药液。白介素－1受体拮抗剂（IL－1ra,50ng/kg)在脑室注射白介素－1β前20min给予。实验以大鼠对光热刺激引起的缩爪反射潜伏期为痛阈指标。结果表明,脑室注射白介素－1β可显著缩短大鼠对光热刺激的缩爪反射潜伏期,并具有剂量依赖性关系。脑室给予500pg/kg的白介素－1β 20min后,大鼠对光热刺激的缩爪反射潜伏期显著缩短,40min时达峰值,然后逐渐恢复。该作用可被白介素－1β受体拮抗剂阻断。结果提示脑中白介素－1β可通过作用于白介素－1受体引起热痛敏作用。

Thermal hyperalgesic effects induced by intracerebroventricular injection of interleukin-1beta in rats

The present study was to investigate the effects of intracerebroventricular (i.c.v.) injection of interleukin-1beta (IL-1beta) on thermal nociception in SD rats. The rats were divided into control and drug-administration groups. The animals of control group were given vehicle solution via i.c.v. injection. The animals of drug-administered groups were given IL-1beta at different doses (5, 50 and 500 pg/kg b.w.) via i.c.v. injection. IL-1 receptor antagonist (IL-1ra, 50 ng/kg) was injected 20 min before injection of IL-1beta or vehicle solution. The nociceptive threshold, which was represented as paw withdrawal latency (PWL), to a noxious thermal stimulation was measured using an analgesiameter. I.c.v. injection of IL-1beta dose-dependently shortened the PWL. At the dose of 500 pg/kg, the shortening of the PWL occurred at 20 min, reaching a peak within 40 min, lasted 100 min after injection, then gradually returned to the baseline level. Pretreatment with IL-1ra completely blocked the effects of IL-1beta-induced shortening in PWL. The results obtained suggest that IL-1beta may induce hyperalgesia in rats through binding to IL-1 receptors in the brain.