阻断肿瘤坏死因子-α的作用对慢性充血性心力衰竭时神经递质失衡的影响

Effect of tumour necrosis factor-α antagonism to attenuate neurotransmitters imbalanced in congestive heart failure

目的 通过中枢阻断肿瘤坏死因子-α（TNF-α）的作用,观察对慢性充血性心力衰竭（心衰）时神经递质失衡的影响,探讨中枢炎性因子对心衰时交感兴奋的作用.方法 采用结扎冠状动脉左前降支致心肌梗死的方法制备心衰大鼠模型,假手术对照只穿线不结扎.对心衰大鼠和假手术大鼠持续4周经侧脑室灌流TNF-α阻断剂依那西普（etanercept,ETN） 10μg/h或人工脑脊液（aCSF）;另一种处理则是以腹腔注射方式给予相似剂量的ETN.4周后测定心脏功能学指标和形态学指标（LVEDP、±dp/dt max、RV/BW、Lung/BW）和肾交感神经放电（RSNA）; ELISA技术测定促炎因子（PIC）在血浆和下丘脑室旁核（PVN）中的含量以及血中血管紧张素Ⅱ（ANGⅡ）水平；PVN中谷氨酸（Glu）、去甲肾上腺素（NE）及血中儿茶酚胺的含量利用高效液相色谱法获得；免疫组织化学染色确定PVN内酪氨酸羟化酶（TH）和谷氨酸脱羧酶（GAD67）,后二者分别为NE和γ-氨基丁酸（GABA）的限速酶,以及神经元型一氧化氮合酶（nNOS）的表达.结果 与假手术组相比,心衰大鼠PVN区NE和TH表达增强,GAD67和nNOS表达减弱；血浆炎性因子、儿茶酚胺、血管紧张素Ⅱ增多；肾交感神经活动增强.对心衰大鼠经侧脑室持续灌流ETN可减轻上述神经递质失衡现象和心衰时肾交感神经的过度兴奋表现；而经腹腔灌注相似剂量的ETN对心衰大鼠PVN处的NE、TH、GAD67和nNOS的含量没有影响,对肾交感神经兴奋也无作用,说明上述影响是通过位于中枢的PIC起作用.结论 心衰时PVN区炎性因子增高,引起中枢兴奋性神经递质增多,抑制性神经递质减少,神经递质平衡失调,从而增强交感兴奋促进心衰发展.

Objective Blocking brain turnout necrosis factor-or （TNF-ot） reduces neurotransmitters imbal- anced in congestive heart failure （HF）. we explored the possible roles of brain proinilammatory cytokines （PIC） on modulating neurotansmi in the exaggerated sympathetic activity in HF. Methods Sprague-Dawley rats were underwent coronary ligation to induce HF or SHAM control. And then, they were treated for 4-weeks with a contin- uous intracerebroventricular （ICV） infusion of the TNF-ct antagonist-etanercept （ ETN, 10 g/h）, or vehicle. Another set of HF and SHAM rats were treated with intraperitoneal （ip） infusion of a similar dose of ETN. After 4 weeks, LVEDP and dp/dt max were measured by hemodynamic measurements. The RV/BW and lung/BW ratios were ealculated. The RSNA was recorded. Plasma and tissue inflammatory cytokine levels, plasma angiotensin 1I ,NE were measured using ELISA techniques. The concentrations of NE and the rate-limiting enzymes of glutamate and GA- BA, respectively, TH and GAD67, and circulating catecholamine levels were measured using HPLC with electro- chemical detection. Immunohistochemical labeUing was performed to identify TH, GAD67 and nNOS in PVN. Results HF rats had increased neuronal excitation accompanied by higher levels of glutamate, norepinephrine（NE）, and tyrosine hydroxylase（TH）, and lower levels of ~/-aminobutyric acid （GABA）, nNOS, and 67-kDa isoform of glu- tamate decarboxylase （GAD67） in the PVN when compared with SHAM rats. Plasma cytokines, NE, epinephrine, anotensin II , and renal sympathetic nerve activity （RSNA） were also increased in HF rats. The same ICV treat- ments also attenuated the increased RSNA in HF rats. IP treatment with similar doses of ETN or ETN did not affect glutamate, NE, TH, GABA, nNOS, and GAD67 in the PVN and had no effect on RSNA of HF rats, Conclusion These findings indicate that brain PICs induce thetic drive in HF. imbalanced and contribute to the increased sympathetic drive in HF.