Figure 4 Effect of mechanical ventilation on the expression of pro‐inflammatory cytokines in rat lungs. (A) Time course of changes in lung mRNA levels of tumour necrosis factor (TNF)α and macrophage inflammatory protein (MIP)‐2 in a rat treated for 4 h with high‐volume (HV) ventilation. The levels of both peaked at 4 h. (B) and (C) Expressions of TNFα (p = 0.03) or MIP‐2 mRNA (p = 0.006) were increased in the lung in the HV group compared with the control group (n = 3 for each group; the increases were attenuated by captopril (**p = 0.045 for TNFα; **0.045 for MIP‐2). (D) The level of MIP‐2 in lung tissue was increased by HV ventilation (*p = 0.001) and was significantly reduced by captopril pretreatment (**p = 0.002; n = 3 for each group). (E) The serum level of MIP‐2 was significantly increased by HV (*p = 0.01) and was reduced by captopril pretreatment (**p = 0.02, n = 3 for each group).