老年和青年大鼠肺泡巨噬细胞凋亡的初步研究

目的探讨大鼠肺泡巨噬细胞(AM)在老年多器官功能衰竭(MOFE)肺启动形成过程中的作用。方法用酵母多糖腹腔注射复制大鼠MOFE模型。实验动物分为老年模型组、老年对照组、青年模型组和青年对照组4组,每组6只鼠。通过支气管肺泡灌洗和细胞贴壁的方法获取AM,用碘化丙啶染色流式细胞仪测定AM凋亡百分率,用Fluo3AM和Rhodamine123染色流式细胞仪测定AM胞内钙、线粒体膜电位。结果老年模型组AM凋亡率明显高于青年模型组(分别为434%±84%和242%±30%,P<001)。模型组与对照组相比,胞内游离钙浓度增加,而线粒体膜电位△Ψm降低。结论老年MOFE大鼠模型的AM的凋亡率大于青年大鼠模型,这可能是MOFE肺部感染后炎症不易控制以及肺部感染或肺损伤后容易引起MOFE的重要原因。AM胞内Ca2+浓度和线粒体膜电位的改变很可能是导致AM凋亡增加的重要原因。

Apoptosis of pulmonary alveolar macrophages in aged and adult rats: a comparative study

OBJECTIVE: To investigate the role of alveolar macrophages (AM) in the initiation of multiple organ failure in the elderly (MOFE). METHODS: Three-month-old (adult) and 24-month-old (aged) males SD rats were used as experimental animals. Zymosan 0.5 g/kg was used to establish animal model of MOFE, normal saline were used among the control rats. The rats were divided into 4 groups: aged model group, aged control group, adult model group, and adult control group. Twenty-four hours after the establishment of model, 6 surviving rats from each group were killed. The trachea, bronthi, and lungs were isolated and lavaged with normal saline. One minute later the bronchi-alveolar lavage fluid (BALF) was re-extracted. Cells were collected from the fluid and put into 24-well cell culture plate. The alveolar macrophages (AMs) adhered to the wall were collected, suspended again, cultured, re-collected, centrifuged, and isolated. Apoptosis of the enriched AM was measured by propidium staining and flow cytometry. Fluo-3.AM staining and flow cytometry were used to detect the intracellular free calcium. Mitochondrial membrane electric potential was detected by rhodamine 123 staining with flow cytometry. RESULTS: The apoptotic rate (APO) of AM in the aged rat models was 43.4% +/- 8.4%, significantly higher than that of adult model rats (24.2% +/- 3.0%, P < 0.01). Compared with the controls, the intracellular calcium increased, but mitochondrial Dgr;Psim decreased in the 2 model groups. CONCLUSION: The AM APO% of aged MOFE model increases. It may be one of the causes of difficulty to control the inflammation in the lung with MOFE and easiness to induce MOFE in elderly when their lungs are infected or injured. Changes of intracellular calcium and mitochondrial Dgr;Psim may play pivotal roles in apoptosis of AM.