| Autor: |
Dong W; Immunotoxicology Branch, United States Environmental Protection Agency, Research Triangle Park; Center for Environmental Medicine and Lung Biology, University of North Carolina, Chapel Hill, USA., Selgrade MK, Gilmour IM, Lange RW, Park P, Luster MI, Kari FW |
| Jazyk: |
angličtina |
| Zdroj: |
American journal of respiratory cell and molecular biology [Am J Respir Cell Mol Biol] 1998 Sep; Vol. 19 (3), pp. 462-9. |
| DOI: |
10.1165/ajrcmb.19.3.3114 |
| Abstrakt: |
Alveolar macrophage functions associated with clearance of bacteria from the lung were assessed in male Fischer 344 rats maintained on a 25% calorie-restricted diet. Calorie-restricted and ad libitum-fed (control) rats were exposed to concentrations of ozone known to compromise phagocytic function of alveolar macrophages. Ozone suppressed alveolar macrophage phagocytosis of latex beads in vitro in ad libitum-fed rats, but not in calorie-restricted rats. In fact, caloric restriction enhanced phagocytic function in both control and ozone-exposed animals. Ad libitum-fed rats exposed to ozone and challenged with Streptococcus zooepidemicus experienced a prolonged infection and influx of polymorphonuclear leukocytes (PMN), whereas calorie-restricted rats exposed to ozone cleared the bacteria in 24 h without an inflammatory response. Bacterial endotoxin-stimulated in vitro production of nitric oxide and tumor necrosis factor (TNF)-alpha as well as expression of TNF-alpha and interleukin-6 messenger RNAs were all lower in alveolar macrophages isolated from calorie-restricted rats. Together, the data suggest that caloric restriction enhances resistance to gram-positive bacteria, while lowering the production of proinflammatory mediators elicited by endotoxin, a component of gram-negative bacteria. Although increased bacterial resistance is considered beneficial, reduction in the lung's ability to induce inflammatory mediators can have both positive and pathophysiologic consequences. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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