[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.


CONCLUSIONS
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.
Qian
Xiao-shun
XS
Institute of Geriatric Cardiology, General Hospital of Chinese People's Liberation Army, Beijing 100853, China.
Zhu
Qing-lei
QL
Yang
Jie
J
Yin
Tong
T
Wang
Shi-wen
SW
D000375:Aging; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002478:Cells, Cultured; D016676:Macrophages, Alveolar / Q000166:cytology*; D008297:Male; D011650:Pulmonary Alveoli / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley