title: Drag-reducing polymers increase exercise tolerance in an ischemic hind-limb rat model.
abstract: OBJECTIVE
  Drag-reducing polymers are long-chain, blood soluble macromolecules that can improve microcirculation in vivo. This study aimed to examine the effects of drag-reducing polymers on exercise tolerance in a rat model of hind-limb ischemia.
  
  
  METHODS
  After adaptive running training, bilateral femoral artery ligation models were established in 64 Wistar rats. During an exhaustive exercise, polyethylene oxide or normal saline was intravenously injected to each group (n = 32) at 4 mL/h for 10 min. The exhaustive exercise time was recorded, and lactic acid levels in gastrocnemius muscle and serum were measured. Serum levels of nitric oxide, creatine kinase and lactate dehydrogenase were measured as biomarkers of physical fatigue.
  
  
  RESULTS
  Compared with saline-treated control group, rats in polyethylene oxide-treated group had longer exhaustive exercise time (774.7 ± 171.5 s vs. 687.6 ± 166.1 s, p = 0.043), and lower lactic acid level in gastrocnemius muscle (p < 0.01) but no significant difference in serum lactic acid level between two groups was observed (p > 0.05). Nitric oxide level was higher in polyethylene oxide group than in controls (p < 0.05), but no significant differences in serum creatine kinase and lactate dehydrogenase levels between two groups were observed (p > 0.05).
  
  
  CONCLUSIONS
  Drag-reducing polymers contribute to the enhancement of exercise endurance and exert anti-fatigue effect.
authors.affiliation: Department of Cardiology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yuanyan
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yili
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China drzha1@163.com.
authors.forename: Daogang
authors.initials: D
authors.lastname: Zha
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D002317:Cardiovascular Agents / Q000008:administration & dosage / Q000494:pharmacology*; D003402:Creatine Kinase / Q000097:blood; D004195:Disease Models, Animal; D017079:Exercise Tolerance / Q000187:drug effects*; D006614:Hindlimb; D007275:Injections, Intravenous; D007511:Ischemia / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D007770:L-Lactate Dehydrogenase / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000098:blood supply*; D009569:Nitric Oxide / Q000097:blood; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000494:pharmacology*; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects; D012420:Running; D013997:Time Factors
chemical_list: D015415:Biomarkers; D002317:Cardiovascular Agents; D009569:Nitric Oxide; D019344:Lactic Acid; D011092:Polyethylene Glycols; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase
keywords: Drag-reducing polymer; acute limb ischemia; exhaustive exercise; polyethylene oxide