Objective: To determine the role of mononuclear macrophages in the pathogenesis of acute lung injury during acute obstructive cholangitis. Methods: Sixty Wistar rats were used to study the correlation between the behavior of mononuclear macrophages and acute pulmonary injury during a- cute obstructive cholangitis (AOC). Animal model of AOC was made according to the method that the common bile duct was injected with Escherichia coli and ligated. The rats were killed at 6 h, 12 h, 24 h and 48 h after operation. The phagocytic function of Kupffer cells (KCs), the number of alveolar macro- phages (AMs) in bronchoalveolar lavage liquid, and the extravascular water content of lung tissue were measured. The levels of lipid peroxide (LPO) and supperoxide dismutase (SOD) were determined too. Pathological alterations of liver and lung tissue were observed under light and electron microscopes. Results: KCs phagocytic function was significantly el- evated at the 6th hour but markedly decreased from the 24th hour to the 48th hour in the AOC group as compared with the control (P<0. 05). From the 12th to the 48th hour, the number of AMs, the ex- travascular water content of lung tissue, and the con- tent of LPO significantly increased, but the SOD lev- el of lung tissue decreased greatly (P<0. 05). Mor- phologically, KCs proliferated diffusely in the early period in livers of the AOC group, but decreased markedly in the late period. Mitochondria of KCs were swollen or even vacuolated; focal cytoplasmic degeneration and many myeli like figures could be seen in the cytoplasm. The changes of injury such as disturbance of pulmonary capillary blood circula- tion, degeneration and/or necrosis of the lung tissue and endothelium, and inflammatory reactions could be observed. In other two groups, no evident mor- phological changes were observed. Conclusions: KCs phagocytic function is decreased, whereas AM is activated by the invading bacteria to release such inflammatory mediators as free radicals, resulting in acute pulmonary injury.
OBJECTIVES: To observe expression of CD14 protein and its gene in Kupffer cells induced bylipopolysaccharide (LPS) and explore the role of CD14 in LPS-induced Kupffer cell activation.METHODS: Kupffer cells were isolated from Wistar rat livers by in situ collagenase digestion, followedby culture and incubation with 100μg/ml LPS for 0, 30, 60 and 120 min, respectively. CD14 proteinexpressed on the membrane of Kupffer cells was examined using confocal microscopy and Western blottinganalysis. Expression of CD14 mRNA in Kupffer cells was determined by reverse transcription polymerasechain reaction (RT-PCR). Tumor necrosis factor (TNF)-α and interleukin (IL)-6 in the supernatantwere measured using enzyme-linked immunosorbent assay (ELISA) kit.RESULTS: Expression of CD14 mRNA and CD14 protein in isolated Kupffer cells was upregullatedquickly after LPS stimulation and increased with time. Likewise, there was a time-dependent increase ofTNF-α and IL-6 in the supernatant with upregulation of CD14 expression. There were significantdifferences between normal and LPS-stimulated Kupffer cells (P<0. 05).CONCLUSIONS: LPS can upregulate expression of CD14 protein and its gene in isolated Kupffer cells.CD14 may play an important role in the activation of LPS-induced Kupffer cells.
