2.3.1. Chemical fixation

The mice were anesthetized by intraperitoneal anesthesia, the right ventricle was bled, the left ventricle was perfused with 2% lanthanum nitrate perfusion solution at a flow rate of 1 mL/min until the kidneys became white, and then perfused with 2% lanthanum nitrate fixative solution. Then the mice aortic and kidney were collected. The mice aorta or kidney tissue, about 1 mm³ in size, was placed in lanthanum nitrate fixative. HUVEC was rinsed three times with PBS and fixed in 2% lanthanum nitrate fixative for 2 h.

Then the specimens were rinsed 4 times, 15 min each time, with 2% lanthanum nitrate rinsing solution. Then the specimens were fixed with 1% osmic acid fixative solution for 2 h; and then the specimens were rinsed 4 times with 2% lanthanum nitrate rinsing solution for 15 min each time.