Figure 3

Expression pattern of HMGB1 in the pulmonary vascular lesion. Immunohistochemical staining with anti-HMGB1 antibody (brown color) and counterstaining with hematoxylin was performed on lung tissues of normal control rats and MCT-induced pulmonary hypertension rats at day 28 after MCT injection. A, C: Sections of large arteries. B, D: Sections of small vessels of lung tissue. (A, B) In normal control rats, HMGB1 was present only in the nuclei of smooth muscle cells (black arrow) and endothelial cells (black triangle). (C, D) However, in MCT-induced pulmonary hypertension rats, HMGB1 was present in both the nuclei and cytoplasm of smooth muscle cells (white arrow) and endothelial cells (white triangle). There were many inflammatory cells around the vessels with cytoplasmic HMGB1 translocation in MCT-induced pulmonary hypertension rats (white asterisk).