Fig. 6
Histological changes of lung tissues detected by light microscope at 200×. a, control group; b, HCl group; c, vagus nerve stimulation (VNS) group; d, tetrahydroaminoacridine (THA) group and e, stellate ganglion block (SGB) group. For control group (n = 8), rabbits only received saline intratracheally injection (2.8 ml/kg) after surgery; for HCl groups (n = 8), ALI model was established by intratracheal injection of HCl (pH 1.5, 2.8 ml/kg); for VNS groups (n = 8), after the ALI model established by HCl, rabbits also received constant voltage stimuli (5 V, 2 ms, and 1 Hz); for THA group (n = 8), after ALI model established by HCl, rabbits also received THA (3 mg/kg) intravenous injection; and for SGB group, after ALI model established by HCl, rabbits also continuously received 0.25% bupivacaine pumping via epidural catheter (3 mg/kg)