Type II Diabetes Mellitus in the Goto‐Kakizaki Rat Impairs Microvascular Function and Contributes to Premature Skeletal Muscle Fatigue

Abstract

Despite extensive investigation into the impact of metabolic disease on vascular function and, by extension, tissue perfusion and organ function, interpreting results for specific risk factors can be complicated by the additional risks present in most models. To specifically determine the impact of type II diabetes without obesity on skeletal muscle microvascular structure/function, and on active hyperemia with elevated metabolic demand, we used 17‐week old Goto‐Kakizaki rats (GK) to study microvascular function at multiple levels of resolution. Gracilis muscle arterioles demonstrated blunted dilation to acetylcholine (both ex vivo proximal and in situ distal arterioles) and elevated shear (distal arterioles only). All other alterations to reactivity appeared to reflect compromised endothelial function associated with increased TxA2 production and oxidant stress/inflammation rather than alterations to vascular smooth muscle function. Structural changes to the microcirculation of GK were confined to reduced microvessel density of ~12%, with no evidence for altered vascular wall mechanics. Active hyperemia with either field stimulation of in situ cremaster muscle or electrical stimulation via the sciatic nerve for in situ gastrocnemius muscle was blunted in GK; primarily due to blunted functional dilation of skeletal muscle arterioles. The blunted active hyperemia was associated with impaired oxygen uptake (VO2) across the muscle and an accelerated muscle fatigue. Acute interventions to reduce oxidant stress (TEMPOL) and TxA2 action (SQ‐29548) or production (dazmegrel) improved muscle perfusion, VO2, and muscle performance. These results suggest that T2DM in GK impairs skeletal muscle arteriolar function apparently early in the progression of the disease and potentially via an increased ROS/inflammation‐induced TxA2 production/action on network function as a major contributing mechanism.Support or Funding InformationAmerican Heart Association and National Institutes of Health (USA); Canadian Institutes for Health Research and Natural Sciences and Engineering Research Council (Canada)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.