Conclusion
Collectively, in the rat small artery structural remodeling and aspects of functional control continue to develop in the immediate postnatal period.
Methods
Rat cerebral and mesenteric arteries were isolated at ages 3, 7, 11, 14, 19 days, 2 months, and 2 years. Using qPCR mRNA expression patterns were examined for elastin, collagen types I, II, III, IV, fibrillin-1, and -2, lysyl oxidase (LOX), and transglutaminase 2.
Results
Elastin, LOX and fibrillar collagens I and III mRNA peaked at day 11-14 in both vasculatures before declining at later time-points. 3D confocal imaging for elastin showed continuous remodeling in the adventitia and the internal elastic lamina for both cerebral and mesenteric vessels. Myogenic responsiveness in cannulated cerebral arteries was detectable at day 3 with constriction shifted to higher intraluminal pressures by day 19. Myogenic responsiveness of mesenteric vessels appeared fully developed by day 3. Functional studies were performed to investigate developmental changes in endothelial-dependent dilation. Endothelial-dependent dilation to acetylcholine was less at day 3 compared to day 19 and at day 3 lacked an endothelial-derived hyperpolarizing factor component that was evident at day 19.