Dietary restriction suppresses inflammation and delays the onset of stroke in stroke-prone spontaneously hypertensive rats

Subjects with high blood levels of inflammatory markers and patients with chronic inflammatory disorders are at high risk for stroke. Dietary restriction (DR) suppresses systemic inflammation to deter age-related chronic diseases. To examine whether DR delays the onset of stroke, 10-week-old stroke-prone spontaneously hypertensive rats (SHRSP) were assigned to either a control (ad libitum) or DR (50% diet of control) group, and day of stroke onset and lifespan were observed. DR markedly delayed the onset of stroke in SHRSP compared to control without affecting blood pressure. Day of stroke onset (median) in the control group was 34 days, whereas it was 70 days in the DR group. After 2 weeks of DR and before the onset of stroke, plasma levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) and their mRNA expression levels in adipose tissue were significantly lower in the DR rats than in the control rats. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mRNA expression levels in cerebrovascular endothelial cells (CVECs), and macrophage infiltration into brain were lower in the DR rats than in the control rats. IL-1β and TNF-α treatment in CVECs increased MCP-1, C-reactive protein, ICAM-1, and VCAM-1 mRNA and their protein levels in vitro. In conclusion, suppression of inflammation in response to DR may lead to a delay in the onset of stroke independent of any effect on blood pressure in SHRSP.

Research highlights
► Dietary restriction (DR) delayed the onset of stroke and extended lifespan in SHRSP.
► DR decreased plasma levels of inflammatory cytokines.
► DR decreased inflammatory cytokine mRNA expressions in visceral adipose tissue.
► DR decreased adhesion molecule mRNA expressions in CVECs.
► DR decreased macrophage infiltration into brain.