Abstract: Objective To observe the effect of Yangxue Qingnao Granule on the ultrastructures and expression of p38 mitogen activated protein kinases (p38MAPK) in CA1 area of hippocampus in vascular dementia rats. Methods 180 Sprague-Dawley rats were randomly divided into sham group, vascular dementia model group (model group) and Yangxue Qingnao Granule treatment group (treatment group). The vascular dementia was modeled with modified Pulsineli's four-vessel occlusion. The ultrastructure of CA1 area was observed with transmission electron microscope, while the expression of p38MAPK in CA1 area was detected with immunohistochemstry and Western blotting 1, 2, 4 and 8 weeks after modeling. Results In the model group, pyknosis, nuclear dissolution, heterochromatin margination and mitochondria swelling were found in most of the neurons in CA1. In the treatment group, the distribution of chromatin was well-proportioned, and mitochondrion and other organelle were normal. In the model group, the expression of p38MAPK increased at each time point compared with the sham group (P<0.01), and peaked 4 weeks after modeling, and decreased in the treatment group compared with the model group (P< 0.01). Conclusion Yangxue Qingnao Granule can improve the ultrastructure of neuronal in CA1 area of hippocampus of vascular dementia rats, which may relate with the inhibition of the expression of p38MAPK.

Key words: vascular dementia, Yangxue Qingnao Granules, p38 mitogen activated protein kinases, ultrastructure, rats