The immunohistochemical stainings of ecNOS in the thoracic aortae 20 h after cecal ligation puncture (CLP) with or without AM/AMBP-1 treatment. ecNOS immunoreaction products were observed in aortic endothelial cells (A-C). No immunostaining was seen in vascular smooth muscle or connective tissues. ecNOS immunohistochemical staining in the vascular endothelial cells was reduced in septic animals (B) compared with sham-operated animals (A). Administration of AM/AMBP-1 attenuated the decreased ecNOS staining (C). There were no immunoreaction products in the negative control section (D). (A), sham 20 h; (B), CLP 20 h; (C), CLP 20 h plus AM/AMBP-1 treatment; (D), negative control.