Figure 6.

Depletion of pulmonary caveolin-1 expression impairs the protective effects of OxPAPC on VILI. A, Polyethylenimine-mediated lung specific transfection¹⁸ and depletion of caveolin-1 in dose-dependent manner. Mice were transfected with nonspecific RNA (nsRNA) or caveolin-1 siRNA at dose of 4, 6, or 10 mg/kg. Depletion of caveolin in different organs (lung, liver, and heart) was verified by Western blot 72 hours after transfection. B, Effects of caveolin-1 depletion on the attenuation of lung vascular leak by OxPAPC in response to HTV. After 4 hours of ventilation, Evans blue dye (30 mL/kg) was injected into the external jugular vein 2 hours before termination of ventilation to assess vascular leak. Lungs were harvested and imaged against white background. Spectrophotometry measurement of extravagated Evans blue was performed as described in Materials and Methods. Insets depict the quantitative measurement of Evans blue–labeled albumin extravasation in the shown lung preparation. Evans blue accumulation in the lungs from small nuclear RNA VILI animals was taken as 100% (n=4 per condition). C, Depletion of caveolin-1 impairs protective effects of OxPAPC on VILI. HTV (30 mL/kg, 4 hours) induced a dramatic increase in BAL total cell count and protein content, which was significantly attenuated by intravenous injection of 1.5 mg/kg OxPAPC in control mice transfected with nonspecific RNA knockdown of caveolin abolished the protective effects of OxPAPC. *P<0.05 ND-no difference, n=4 per group.