Date of Award
Master of Science
Health and Rehabilitation Sciences
Dr. Jamie Meiling
Type 1 Diabetic Mellitus (T1DM) patients can develop insulin insensitivity partially due to the daily requirement of exogenous insulin. Regular exercise has been shown to improve insulin sensitivity (IS) partially though the increased expression of skeletal muscle GLUT4 and insulin receptor (IR) content. Although exercise is beneficial in increasing IS, exercise presents a problem in the T1DM population, as it leads to uncontrolled fluctuations in blood glucose (BG) concentrations. This study examined the effect of aerobic and resistance training exercises on IS and fluctuations in BG concentrations in T1DM rats. Fifty animals were randomly divided into 5 groups; control (C), control diabetic (CD), diabetic resistance exercised (DR), diabetic high intensity aerobic exercised (DH) and diabetic low intensity aerobic exercised (DL). CD, DR, DH and DL were injected with streptozotocin (STZ) and insulin pellets were
subcutaneously implanted to maintain blood glucose concentrations between 9 and 15 mmol/L. DR climbed a ladder with weights secured to the tail; they performed 6-10 climbs per exercise bout and weights were increased every 3 days to ensure that rats were lifting maximal weight. They performed exercise bouts 5 days/week for 6 weeks. DH ran on a treadmill at 27 m/min and 6% grade, 1 hour/day, 5 days/week for 6 weeks. DL ran on a treadmill at 15 m/min and 6% grade, 1hour/day, 5 days/week for 6 weeks. At 3 and 6 weeks, BG clearance rates in all groups were lower than C (p<0.05). At 6 weeks, DR, DH and DL also had greater BG clearance rates than CD (p<0.05). IR protein content in the white gastrocnemius muscle (WG) was elevated in DH, compared to C and CD (p<0.05), and in DL, compared to C, CD and DR (p<0.05). GLUT4 protein content in the white portion of the vastus lateralis muscle was increased in DH, compared to CD
and DL (p<0.05), and in DR, compared to DL (p<0.05), while CD and DL demonstrated a decrease in GLUT4, compared to C (p<0.05). GLUT4 protein content in the red portion of the vastus lateralis was elevated in DH, compared to C, CD, DR and DL (p<0.05). GLUT4 content in DL was lower than in C (p<0.05). GLUT4 protein content in the WG was increased in DR, compared to CD and DL (p<0.05) and in DH, compared to CD (p<0.05). In the DR group, exercise lead to a significant drop in BG concentrations 1 hour post exercise, when compared to pre-exercise BG concentrations, at weeks 3 and 6 (p<0.05). At weeks 3 and 6, DH experienced a significant drop in BG concentrations post-exercise, which restored to pre-exercise values at 45 and 75 minutes (p<0.05). In week 3, DL experienced a decrease in BG concentrations for 2 hours post exercise (p<0.05). In week 6 however, DL experienced an increase in BG concentrations at 30, 105 and 120 minutes post exercise (p<0.05). To conclude, T1DM rodents exhibit insulin insensitivity, which was alleviated through regular exercise. In addition, different training modalities lead to different alterations in protein content and exercise induced fluctuations in BG concentrations. Specifically, aerobic exercise lead to immediate falls in BG, where as resistance exercise lead to a more gradual fall in BG concentrations.
Hall, Katherine, "THE EFFECT OF AEROBIC AND RESISTANCE EXERCISE ON INSULIN SENSITIVITY AND GLYCEMIC CONTROL IN TYPE 1 DIABETIC RATS" (2011). Digitized Theses. 3531.