慢性情绪应激对高脂饮食大鼠炎症反应和主动脉Toll样受体4表达的影响

目的通过观察慢性情绪应激对高脂饮食大鼠脂代谢、炎症反应和主动脉内皮细胞TLR4表达的影响,探讨慢性情绪应激在动脉粥样硬化病变形成中的作用、机制。方法雄性Wistar大鼠40只,随机分为正常对照组(NC)、无应激组(NS)、生理应激组(PS)和情绪应激组(ES),每组各10只,并制作慢性情绪应激模型。于末次应激结束后采集血标本,全自动生化分析仪检测血清TC、TG、HDL-C、LDL-C和hs-CRP,ELISA法测定血清ox-LDL、放免法检测TNF-α水平;HE染色观察大鼠主动脉形态学变化;免疫组化法(S-P)测定主动脉内皮细胞TLR4表达。结果 (1)ES组大鼠较其他3组出现了明显的脂代谢紊乱和炎症反应。与PS组、NS组、NC组比较,ES组TC、LDL-C、ox-LDL水平明显升高[TC:(5.30±0.69)mmol/L比(3.94±0.42)mmol/L、(3.82±0.48)mmol/L、(2.07±0.26)mmol/L;LDL-C:(1.57±0.22)mmol/L比(1.18±0.13)mmol/L、(1.11±0.11)mmol/L、(0.75±0.11)mmol/L;ox-LDL:(65.18±6.51)μg/dl比(45.65±2.70)μg/dl、(38.35±2.27)μg/dl、(14.99±1.46)μg/dl,均为P<0.01];ES组HDL-C[(0.94±0.14)mmol/L]低于NS组[(1.09±0.14)mmol/L,P<0.05],低于NC组[(1.16±0.18)mmol/L,P<0.01];与PS组、NS组、NC组比较,ES组hs-CRP、TNF-α水平升高[hs-CRP:(1.748±0.082)mg/L比(1.485±0.067)mg/L、(1.381±0.067)mg/L、(0.757±0.069)mg/L;TNF-α:(2.447±0.083)μg/L比(2.189±0.099)μg/L、(2.181±0.085)μg/L、(1.772±0.075)μg/L,均为P<0.01];(2)ES组大鼠主动脉出现早期动脉粥样硬化性改变;(3)ES组大鼠主动脉内皮细胞TLR4表达明显上调,其阳性细胞单位面积平均吸光度值(A)高于PS组、NS组和NC组[(0.334±0.010)比(0.250±0.012)、(0.238±0.015)、(0.082±0.008),均为P<0.01]。结论慢性情绪应激可能在动脉粥样硬化形成的早期,部分通过激活TLR4释放炎性细胞因子引起机体的炎症反应,进而导致动脉粥样硬化病变形成。

Effects of chronic emotional stress on inflammation and expression of Toll-like receptor 4 in aorta in rats fed with high-fat diet

Objective To investigate the effects of chronic emotional stress on serum lipids,inflammatory response and expression of Toll-like receptor(TLR) 4 in aorta in rats fed with high-fat diet.Methods Forty male Wistar rats were divided into 4 groups(10 in each group) randomly: normal control group(NC),no-stress group(NS),physical stress group(PS) and emotional stress group(ES).The chronic emotional stress model was made.The blood samples were immediately obtained after the last stress for assay of serum lipids and hs-CRP.The level of TNF-α in serum was measured by radioimmunoassay kit and ox-LDL in serum was measured by the enzyme-linked immunosorbent assay(ELISA).HE staining was used to detect the change of rat aorta and immunohistochemistry was used to detect the change of expression of TLR4 in rat aorta.Results(1) The rats in ES group showed more evident lipid metabolism disorders and inflammation.Compared with PS group,NS group and NC group,the level of TC,LDL-C,ox-LDL in ES group were significantly elevated [(5.30±0.69) mmol/L vs.(3.94±0.42) mmol/L,(3.82±0.48) mmol/L,(2.07±0.26) mmol/L for TC;(1.57±0.22) mmol/L vs.(1.18±0.13) mmol/L,(1.11±0.11) mmol/L,(0.75±0.11) mmol/L for LDL-C;(65.18±6.51) μg/dl vs.(45.65±2.70) μg/dl,(38.35±2.27) μg/dl,(14.99±1.46) μg/dl for ox-LDL,all P<0.01];HDL-C level was lower in ES group[(0.94±0.14) mmol/L] than that in NS group [(1.09±0.14) mmol/L],and in NC group [(1.16±0.18) mmol/L,all P<0.01].Compared with PS group,NS group and NC group,the level of hs-CRP,TNF-α in ES group were elevated [(1.748±0.082) mg/L vs.(1.485±0.067) mg/L,(1.381±0.067) mg/L,(0.757±0.069) mg/L for hs-CRP,(2.447±0.083) μg/L vs.(2.189±0.099) μg/L,(2.181±0.085) μg/L,(1.772±0.075) μg/L for TNF-α,all P<0.01].(2) HE staining showed the ES group had early atherosclerotic changes.(3) The expression of TLR4 was at a higher level in ES group.The mean absorbance value of positive cells per unit area(A) was significantly higher in ES group than those in PS group,NS group and NC group[(0.334±0.010) vs.(0.250±0.012),(0.238±0.015),(0.082±0.008),all P<0.01].Conclusions Chronic emotional stress may be promoting vessel wall inflammation partly by release of proinflammatory cytokins TLR4 induced in the early formation of the atherosclerotic lesion.