n-3多不饱和脂肪酸对心脏移植物血管病变的影响

Effects of n-3 fatty acids on cardiac allograft vasculopathy

背景:鱼油中的大量n-3多不饱和脂肪酸能抑制心脏移植物血管病变,延长移植物存活时间,但机制尚不完全清楚。新近研究提示,在体外实验中n-3多不饱和脂肪酸可通过活化过氧化物酶增殖子活化受体γ(peroxisome proliferator-activate receptor-γ,PPARγ)抑制炎性递质释放。目的:拟证实活化PPARγ是否为n-3多不饱和脂肪酸缓解心脏移植物血管病变的新机制之一。方法:随机选取6只Lewis大鼠及18只Fisher344作为心脏供体。抽签法将另外24只Lewis大鼠随机分为4组作为受体每组6只:同系移植组:Lewis大鼠之间心脏移植,不给予任何药物;低剂量鱼油组:行F344→Lewis异系移植,术后第1天开始按0.03mL/kg给予鱼油灌胃8周;高剂量鱼油组:行F344→Lewis异系移植,术后第1天开始按0.06mL/kg给予鱼油灌胃8周;对照组:行F344→Lewis异系移植,给予等体积环孢素A灌胃8周。低、高剂量鱼油组均在移植后开始环孢素A1.5mg/(kg·d)肌注2周。组织学检查评价心脏移植物血管病变,组织匀浆测定核因子κB及PPARγ活性,ELIS测定单核趋化蛋白1、干扰素诱导蛋白10含量,实时定量PT-PCR检测趋化因子受体CCR2及CXCR3表达。结果与结论:所有24只受体Lewis大鼠术后均顺利存活,供心在移植后8周仍有规律搏动。与同系移植组相比,移植周后对照组心脏移植物发生了严重心脏移植物血管病变。与对照组相比,高、低剂量鱼油组心脏移植物血管病变均显著缓解,PPARγ活性显著提高,核因子κB活性显著下降,组织匀浆单核趋化蛋白1及干扰素诱导蛋白10含量显著降低,趋化因子受体CCR2表达亦显著下调(P<0.001,P<0.05),高剂量鱼油组作用更明显(P<0.05)。高、低剂量鱼油组及对照组CXCR3表达差异无显著性意义。实验证实,n-3多不饱和脂肪酸可通过活化核蛋白PPARγ抑制核因子κB活性与趋化因子及其受体表达,呈剂量依赖性缓解近交系大鼠模型心脏移植物血管病变的发生及发展。

BACKGROUND：Fish oil is one of mainly natural resources of n-3 fatty acids,which can inhibit cardiac allograft vasculopathy（CAV） and prolong the survival of cardiac allograft.But,the mechanism is unclear.Recent in vitro data suggested that n-3 fatty acids could inhibit the release of inflammatory transmitter by the activation of peroxisome proliferator-activated receptor-γ（PPARγ）.OBJECTIVE：To test the hypothesis that n-3 fatty acids from fish oil ameliorates CAV development via activating PPARγ.METHODS：A total of 6 Lewis rats and 18 Fisher344 rats were randomly selected as heart donors.An additional 24 Lewis rats were randomly and equally divided into 4 groups.In isograft group,heart transplantation was performed among Lewis rats,without any drug.In low-dose fish oil-treated group,F344→Lewis transplantation was performed.At 1 day following surgery,0.03 mL/kg fish oil was treated by gavage for 8 weeks.In high-dose fish oil-treated group,F344→Lewis transplantation was conducted.At 1 day following surgery,0.06 mL/kg fish oil was treated by gavage for 8 weeks.In control group,F344→Lewis transplantation was conducted.Cyclosporine A was administrated by gavage for 8 weeks.In the low-dose and high-dose fish oil-treated groups,cyclosporine A（1.5 mg/kg） was given daily by intramuscular injection for 2 weeks following surgery.CAV was evaluated by histological examination.Activity of nuclear factor（NF） κ-B and PPARγ was assessed in homogenate.Contents of monocyte chemoattractant protein-1 and interferon-inducible protein 10 were measured by enzyme-labeled immunosorbent assay（ELISA）.Chemokine receptor CCR2 and CXCR3 expression was determined by real-time quantitative reverse transcription-polymerase chain reaction（RT-PCR）.RESULTS AND CONCLUSION：All 24 receptor Lewis rats were survived following surgery.The donor heart could regularly beat at 8 weeks following transplantation.Compared with the isograft group,severe CAV was detected in the control group at 8 weeks.Compared with the control group,CAV was significantly relieved,the activity of PPARγ was significantly elevated,the activity of NF κ-B was significantly decreased,levels of intragraft monocyte chemoattractant protein-1 and interferon-inducible protein-10 were significantly reduced in the low-dose and high-dose fish oil-treated groups（P0.001,P0.05）,especially in the high-dose fish oil-treated group（P0.05）.There was no significant difference in expression of chemokine receptors CXCR3 in the low-dose and high-dose fish oil-treated groups and control group.Our results demonstrated that n-3 fatty acids from fish oil can attenuate CAV development,possibly through activating PPARγ and subsequently inhibiting the NF-κB activation,the chemokines secretion and its receptor expression in a dose-dependent fashion in rat models.