Perivascular macrophages produce type I collagen around cerebral small vessels under prolonged hypertension in rats

In this study, we examined if perivascular macrophages (PVMs) are involved in collagen production around cerebral small vessels in hypertensive SHRSP/Izm rats. Immunoreactivity for type I collagen around cerebral small vessels in 12-week-old hypertensive rats tended to higher than those in 4-week-old hypertensive and 12-week-old control rats. In ultrastructural analyses using transmission electron microscopy, the substantial deposition of collagen fibers could be observed in the intercellular spaces around PVMs near the arterioles of rats with prolonged hypertension. In situ hybridization analyses revealed that cells positive for mRNA ofCol1a1, which comprises type I collagen, were observed near cerebral small vessels. TheCol1a1-positive cells around cerebral small vessels were colocalized with immunoreactivity for CD206, a marker for PVMs, but not with those for glial fibrillary acidic protein or desmin, markers for other perivascular cells such as astrocytes and vascular smooth muscle cells. These results demonstrated that enhanced production of type I collagen is observed around cerebral small vessels in rats with prolonged hypertension andCol1a1 is expressed by PVMs, and support the concept that PVMs are involved in collagen production and vascular fibrosis under hypertensive conditions.
Source: Histochemistry and Cell Biology - Category: Biomedical Science Source Type: research