Microvascular network shear rate is disrupted with elevated tissue bath glucose in normal mice

Abstract-Blood glucose levels reflect interstitial glucose in both normal and diabetics patients. Long term elevated blood glucose adversely affects shear sensing in the microcirculation. We have shown that there is a predictable axial gradient in shear within arteriolar networks. We hypothesized that elevated interstitial glucose levels in non-diabetic mice would disrupt axial gradients in shear rate (SR). Networks were observed in the cremaster muscle of anesthetized (n ) C57BL/ mice before and after 2 hours exposure to tissue bath glucose (Glc). Diameter (D) and red blood cell (RBC) velocity (V) were measured and SR rate was calculated ( V/D). In controls, SR was lower for the feed compared to associated branches, with SR in the upstream branches higher and more variable than in the last branch of the network. With Glc SR decreased in the feed all cell flux was diverted from upstream branches to the last branch of the network. Feed diameter dilated, but branch diameter was unaffected by glucose thus changes in SR were not attributed to changes in resistance alone. We conclude that only 2 hours of high glucose adversely affected flow distribution and axial shear gradients within this muscle preparation.