Hindlimb unweighting for 14 days decreased endothelium-dependent vasodilation, eNOS expression, and SOD-1 expression primarily in arteries of soleus muscle where blood flow is reduced.
We tested the hypothesis that hindlimb unweighting (HLU) decreases endothelium-dependent vasodilation and expression of endothelial nitric oxide synthase (eNOS) and superoxide dismutase-1 (SOD-1) in arteries of skeletal muscle with reduced blood flow during HLU. Sprague-Dawley rats (300-350 g) were exposed to HLU (n = 15) or control (n = 15) conditions for 14 days. ACh-induced dilation was assessed in muscle with reduced soleus (Sol) or unchanged gastrocnemius (Gast) blood flow during HLU. eNOS and SOD-1 expression were measured in feed arteries (FA) and in first-order (1A), second-order (2A), and third-order (3A) arterioles. Dilation to infusion of ACh in vivo was blunted in Sol but not Gast. In arteries of Sol muscle, HLU decreased eNOS mRNA and protein content. eNOS mRNA content was significantly less in Sol FA (35%), 1A arterioles (25%) and 2A arterioles (18%). eNOS protein content was less in Sol FA (64%) and 1A arterioles (65%) from HLU rats. In arteries of Gast, HLU did not decrease eNOS mRNA or protein. SOD-1 mRNA expression was less in Sol 2A arterioles (31%) and 3A arterioles (29%) of HLU rats. SOD-1 protein content was less in Sol FA (67%) but not arterioles. SOD-1 mRNA and protein content were not decreased in arteries from Gast. These data indicate that HLU decreases endothelium-dependent vasodilation, eNOS expression, and SOD-1 expression primarily in arteries of Sol muscle where blood flow is reduced during HLU.
Woodman et al. (Sat,) conducted a other in Hindlimb unweighting (n=30). Hindlimb unweighting (HLU) vs. Control conditions was evaluated on ACh-induced dilation and eNOS/SOD-1 expression in arteries of skeletal muscle. Hindlimb unweighting for 14 days decreased endothelium-dependent vasodilation, eNOS expression, and SOD-1 expression primarily in arteries of soleus muscle where blood flow is reduced.