As previously reported, the cerebral arterioles are surrounded by unique perivascular Mato cells. They contain many inclusion bodies rich in hydrolytic enzymes, and have strong uptake capacity. They are thus considered scavenger cells of vascular and neural tissues in steady-state. In this study, employing hypertensive SHR-SP (Izm) rats, the viability of Mato cells was investigated. In hypertensive rats, the capacity for uptake of horse radish peroxidase (HRP) and the activity of acid phosphatase (ACPase) of Mato cells were markedly reduced, and on electron-microscopic examination Mato cells were found to include heterogeneous contents and appeared electron-dense and degenerated. Vascular cells exhibited some signs of pathology. However, in hypertensive rats fed chow containing 0.25% cocoa, the uptake capacity and ACPase activity of Mato cells for HRP were enhanced, and on electron-microscopic examination Mato cells appeared healthy, with mitochondria with nearly normal profiles. Signs of pathology in vascular cells were also decreased. Superoxides may impair Mato cells and vascular cells.
Keywords: Mato cell; SHR-SP (Izm) rat; cocoa; hypertension; superoxide.