OBJECTIVETo investigate the effect of aging on the expressions of monocyte chemoattractant protein 1 (MCP-1) and intercellular adhesion molecule 1 (ICAM-1) in the lung tissue of rats with lipopolysaccharide (LPS)-induced acute lung injury (ALI).

METHODSBoth young (3 months old) and aged (27 months old) female Wistar rats were randomly divided into two groups (n=8), namely the normal control and LPS-induced ALI groups. Immunohistochemistry for of ED-1 was used to detect the infiltrating inflammatory cells. Western blot and Northern blot analyses were employed for evaluating the expressions of MCP-1 and ICAM-1 at the protein and mRNA levels.

RESULTSVirtually no ED-1-positive cells were found in the lung tissue of the control rats in the young and aged groups. After LPS-induced ALI, ED-1-positive cells in the lung tissues increased significantly in both young and aged groups (P<0.05), and the increment was more obviously in the aged group (P<0.05). In the two normal control groups, the aged rats showed significantly higher expressions of MCP-1 and ICAM-1 than the young rats (P<0.05); LPS significantly up-regulated their expression in the young and aged groups (P<0.05), but the latter showed greater increments (P<0.05). The aged rats with ALI also showed significantly greater MCP-1 and ICAM-1 increments than those of the young rats (P<0.05).

CONCLUSIONSAging may upregulate lung MCP-1 and ICAM-1 expressions and enhance LPS-induced increments of MCP-1 and ICAM-1 expressions to exacerbate the pulmonary inflammation in rats.