Fig. 6.

PD-L1 gene suppression by intravenous (I.V.), but not intratracheal (I.T.), siRNA delivery markedly attenuated the increase in local lung tissue levels of inflammatory cytokine/chemokine produced in response to hemorrhagic shock followed by cecal ligation and puncture (Hem-CLP). TNF-α, IL-6, IL-10, KC, MCP-1, and MIP-2 levels in tissue homogenate samples were increased after Hem-CLP compared with sham mice. The levels of IL-6, MCP-1, and MIP-2 were significantly decreased in samples from the intravenous (A), but not the intratracheal (B), delivered anti-PD-L1 siRNA-treated indirect acute lung injury (iALI) groups. No changes were seen in TNF-α, IL-10, and KC levels from both intravenous and intratracheal delivery-treated iALI groups. Values are means ± SE; n = 6–10 mice per group; *P < 0.05 vs. sham; #P < 0.05 vs. PD-L1 siRNA-treated group, by one-way ANOVA and a Student–Newman–Keuls test.