Figure 3.

IT administration of PKCδ-TAT attenuates neutrophil migration into rat lung and attenuates ICAM-1 expression in sepsis-induced indirect lung injury. Immunohistochemical detection of MPO in representative lung tissue sections from 24 hours after surgery (n = 4 animals per group). In the sham surgery group, only a few MPO⁺ cells were seen in each field. In the CLP+PBS group, sepsis induced infiltration of numerous MPO⁺ cells throughout the lung parenchyma. Administration of the TAT-TAT control peptide had no significant effect on sepsis-induced influx of MPO⁺ cells into the parenchyma, compared with CLP+PBS vehicle. Administration of the inhibitory peptide led to a significant reduction of sepsis-induced MPO⁺ cell numbers in the lung. After primary antibody incubation, ICAM-1 was visualized using an Alexa Fluor 488–conjugated secondary antibody (green), with DAPI counterstaining (blue). Representative lung tissue sections from 24 hours after surgery are shown (n = 4 animals per group). In the sham surgery group, levels of ICAM-1 were barely detectable. In the CLP+PBS group, widespread and intense sepsis-induced ICAM-1 staining throughout the lung parenchyma was observed. In the CLP+TAT-TAT group, high levels of ICAM-1 were observed, with distribution similar to that of the CLP+PBS group. In the CLP+PKCδ-TAT group, marked reduction in sepsis-induced ICAM-1 expression was observed, with some small patches of staining seen in alveoli. Scale bars: 50 μm (left column); 100 μm (right column).