血管活性肠肽对帕金森病大鼠中缝背核5-HT、SP、CRF及CRFR2表达的影响

The effects of VIP on the expression of 5-HT,SP,CRF,CRFR2 and its mRNA in the dorsal raphe nucleus of rats with Parkinson's disease

目的:研究血管活性肠肽(VIP)对5-羟色胺(5-HT)、P物质(SP)、促肾上腺皮质激素释放因子(CRF)及其受体CRFR2在帕金森病(PD)大鼠中缝背核(DRN)表达的影响,探讨VIP对PD发病中与抑郁有关的神经激素的可能作用。方法:采用单侧纹状体注射神经毒素6-羟多巴胺(6-OHDA)建立PD模型大鼠,将PD大鼠随机分为模型组和VIP组(在造模成功后开始腹腔注射VIP 25 ng/kg,1次/2 d,连续15 d),每组10只。另10只正常大鼠纹状体注射生理盐水作为对照组。采用免疫组织化学法观察中缝背核内5-HT、SP、CRF、CRFR2阳性细胞的分布、形态及数量的变化。RT-PCR法检测色氨酸羟化酶2(5-HT合成的限速酶-TPH2)mRNA、SP mRNA、CRF mRNA及CRFR2 mRNA的表达变化。结果:免疫组化结果显示:与对照组比较,模型组大鼠中缝背核内5-HT阳性神经元胞体较小,其数量明显减少(P<0.01),细胞分布稀疏,SP、CRF、CRFR2阳性细胞数明显增加(P<0.01),分布密集。经VIP治疗后大鼠中缝背核内5-HT阳性神经元的数目较模型组显著增加(P<0.01),胞体呈中等大小,而SP、CRF、CRFR2阳性细胞数则显著减少(P<0.01),分布稀疏。RT-PCR检测其相应的mRNA表达结果与免疫组织化学染色结果趋势相同。结论:VIP对抑郁相关神经内分泌激素5-HT、SP、CRF及CRFR2的表达有影响。

Objective： To explore the effects of vasoactive intestinal peptide （VIP） on the expression of 5- hydroxytryptamine （5-HT）, substance P （ SP）, corticotropin-releasing factor （CRF） and CRF type 2 receptor （CRFR2） in the dorsal raphe nucleus （DRN） of Parkinson＇s disease （PD） rats, and to discuss the possible roles of VIP on the de- pression-related neurohormones in PD. Methods： PD rat models were prepared by injecting neurotoxin 6-hydroxydopamine （6-OHDA） into the fight striatum. Twenty PD rats were randomly divided into the model group and the VIP group [ VIP was injected intraperitoneally （25 ng/kg,/PD rat） every 2 days for 15 days] , and 10 rats in each group. Another 10 adult normal rats were injected saline instead of 6-OHDA as the control group. The changes of distribution, morphology and number of 5-HT-, SP-, CRF-and CRFR2-positive cells in dorsal raphe nucleus （DRN） of rats in three groups were exam-ined by immunohistochemical methods. The expressions of tryptophan hydroxylase 2 （ TPH2 is 5-HT synthesis rate-limit- ing enzyme） mRNA, SP mRNA, CRF mRNA and CRFR2 mRNA were detected by RT-PCR. Results：Compared with the control group, the 5-HT-positive neurons with smaller size distributed sparely in DRN of the PD rats in the model group, and its number was obviously decreased （P 〈 0.01 ）. The numbers of SP-, CRF- and CRFR2-positive neurons were in- creased significantly in the model group （P 〈 0.01 ）, and these immunoreactive cells distributed densely. Compared with the model group, the number of 5-HT-positive neurons in the VIP group was obviously increased （ P 〈 0.01 ）, and the neurons were medium size. The numbers of SP-, CRF- and CRFR2=positive cells were decreased significantly （P 〈 0.01 ）, and these cells distributed sparely in the VIP group. The expression trend of 5-HT mRNA, SP mRNA, CRF mR- NA and CPtFR2 mRNA were consistent with the immunohistochemical results. Conelusion：VIP has the effect on the ex- pression of depression-related 5-HT, SP, CRF and CRFR2 in DRN of PD rat