[Perfluorocarbons injected intraperitoneally suppress neutrophilic infiltration in lipopolysaccharide-induced lung injury in rats].

Objective: To explore the suppressive effects of perfluorocarbon (PFC, C(8)F(18)) injected intraperitoneally on neutrophilic infiltration in lipopolysaccharide (LPS)-induced lung injury in rats.

Methods: A hundred and eight Wistar rats were randomly divided into 4 groups, and with 9 rats in each of the 3 time points respectively: Normal control group (NC group), PFC control group (PFC group), LPS-induced acute lung injury group (LPS group) and PFC pre-treatment group (PFC + LPS group). The animals were injected intraperitoneally with PFC at dose of 15 ml/kg in PFC group and PFC + LPS group 48 hours before. LPS at dose of 7 mg/kg injected via penile vein induced lung injury at LPS group and PFC + LPS group and the animals were respectively killed by exsanguination at 2, 4, 6 hour points. The white blood cells and neutrophils were counted in bronchoalveolar lavage fluid (BALF) and venous blood, and the neutrophils were counted in lung tissue under microscope. The expression of E-selectin and intercellular adhesion molecule-1 (ICAM-1) were immunohistochemically detected in lung tissue as integrated optic density (IOD) measured with Image Pro Plus 5.1 software.

Results: (1) The counts of white blood cells of BALF [(1.98 +/- 0.21), (2.98 +/- 0.43), (3.95 +/- 0.29) x 10(6)/L at three times points respectively] and PMN percentages (0.170 +/- 0.069, 0.250 +/- 0.046, 0.351 +/- 0.054 at times points respectively) in LPS group significantly increased as compared with those in NC group [(1.27 +/- 0.20), (1.27 +/- 0.18), (1.26 +/- 0.11) x 10(6)/L and 0.041 +/- 0.008, 0.041 +/- 0.007, 0.041 +/- 0.007 at three times points respectively, t = 5.680 - 18.924, all P < 0.01]. The counts of white blood cells and PMN percentages of BALF in PFC + LPS group [(1.45 +/- 0.39), (2.67 +/- 0.44), (3.29 +/- 0.45) x 10(6)/L and 0.065 +/- 0.024, 0.102 +/- 0.033, 0.174 +/- 0.049 at times points respectively] significantly reduced as compared with those of LPS group (t = -4.224 - 12.033, P < 0.01). (2) On the contrary, the counts of white blood cells of venous blood in LPS group [(5.26 +/- 0.85), (4.38 +/- 0.39) x 10(9)/L at 4, 6 h] were significantly lower than NC group [(6.29 +/- 0.55), (6.28 +/- 0.60) x 10(9)/L, t = -3.088 and -7.946, P < 0.01], whereas the PFC pre-treatment significantly increased the counts. (3) In lung tissue, the counts of PMN per field (7.56 +/- 1.81, 18.76 +/- 3.51 and 33.99 +/- 5.68), the expressions of E-selectin (IOD: 208 +/- 78, 283 +/- 67 and 625 +/- 85) and ICAM-1 (IOD: 208 +/- 78, 283 +/- 67 and 625 +/- 85) in PFC + LPS group were significantly decreased compared with LPS group (10.78 +/- 0.92, 31.55 +/- 3.00 and 54.14 +/- 5.49; 1,086 +/- 256, 1,606 +/- 408 and 3,409 +/- 1,751; 299 +/- 97, 378 +/- 67 and 817 +/- 149, respectively, t = -2.400 - 11.480, P < 0.01) at three time points.

Conclusion: PFC pre-injected intraperitoneally significantly suppressed the neutrophilic infiltration in LPS-induced lung injury and reduced the expressions of E-selectin and ICAM-1 as the possible molecular mechanism of its effects.