高脂饮食兔肺泡巨噬细胞[Ca^(2+)]_i及ACE活性变化

Changes of [Ca^(2+)]_i and the activity of ACE in alveolar macrophages of rabbits with high-fat diet

目的:了解高脂饮食对兔肺泡巨噬细胞胞浆游离钙浓度([Ca2+]i)及血管紧张素Ⅰ转换酶(ACE)活性的影响,探索哮喘与高脂饮食相关的可能机制。方法:高胆固醇饮食法建立高脂兔模型(n=6),8周后离体支气管肺泡灌洗;Fura2/am测定肺泡巨噬细胞[Ca2+]i,紫外法检测ACE活性。结果:高脂组肺泡巨噬细胞[Ca2+]i显著高于正常组(P<0.01);其支气管肺泡灌洗液(BALF)及肺泡巨噬细胞上清液中ACE活性显著高于正常组(均P<0.01);高脂组BALF中肺泡巨噬细胞数、肺泡巨噬细胞[Ca2+]i及肺泡巨噬细胞培养上清液ACE活性均与血清总胆固醇含量呈正相关,r分别为0.851、0.840、0.847(均P<0.05)。结论:高脂饮食导致兔肺泡巨噬细胞活化,活性增高的肺泡巨噬细胞处于易激状态。

AIM： To investigate the effects of high - fat diet on the level of intracellular free calcium （[Ca^2＋]i） and the activity of angiotensin Ⅰ converting enzyme （ACE） in alveolar macrophages （AMs） of rabbits. The association between asthma and high - fat diet was also observed. METHODS： Twelve male New Zealand rabbits were medially divided into normal diet group and 1.2% high - cholesterol diet group randomly. 8 weeks later, bronchial alveolar layage was performed in vitro. [Ca^2＋]i was determined by Fluo - 2/am. The activity of ACE was detected with ultraviolet method. RESULTS： The levels of [Ca^2＋]i in AMs greatly increased （P 〈0.01 ）. The activity of ACE both in BALF and in culture supernatants of AMs was all greatly increased compared with normal diet group （ P 〈0. 01 ）. In hypercholesterolemic group the number of macrophages in BALF showed a positive correlation with the content of cholesterol in serum, such as the level of [Ca^2＋]i in AMs and the activity of ACE in the culture supernatants of AMs （ all P 〈 0. 05 ）. CONCLUSION： The results suggest that AMs of rabbits may be activated by hyperlipoidemia and become ease to be stimulated.