Differential Effects of Treadmill Exercise on Calretinin Immunoreactivity in Type 2 Diabetic Rats in Early and Chronic Diabetic Stages

Abstract

ABSTRACT. In this study, we investigated the effects of treadmill exercise on calretinin (CR), a marker of early postmitotic neurons, immunoreactivity in the dentate gyrus (DG) of Zucker diabetic fatty (ZDF) rats, before or after diabetes onset, and Zucker lean control (ZLC) rats. For this study, 6-week-old ZLC and prediabetic ZDF rats, and 22-week-old ZLC and ZDF rats were exercised on the treadmill. Sedentary ZLC and ZDF rats of the same age were used as exercise experiment controls. The exercised prediabetic ZDF rats did not show diabetes onset, while the sedentary prediabetic ZDF rats showed significantly increased blood glucose levels. The exercised diabetic ZDF rats exhibited a decrease in their blood glucose levels compared to the sedentary diabetic ZDF rats, but the levels were still above 20 mmol/l. ZLC rats of both ages were in the normoglycemic range. CR immunoreactivity was detected throughout the DG, including the subgranular zone and the polymorphic layer. Diabetic rats exhibited a significant decrease in the number of CR-immunoreactive cells and fibers in the DG. Exercise in the prediabetic ZDF rats significantly increased the number of CR-immunoreactive cells and fibers in the subgranular zone of the DG. In the ZLC and ZDF rats of chronic diabetic phase, exercise increased CR-immunoreactive neurons in the hilar region. These results suggest that diabetes significantly reduces the number of postmitotic CR-immunoreactive neurons and the intensity of immunoreactivity and that exercise increases these CR-related parameters in a diabetic stagedependent manner.

Exercise Affects Blood Glucose Levels and Tissue Chromium Distribution in High-Fat Diet-Fed C57BL6 Mice

“…The growing prevalence of obesity and its association with diabetes, hypertension, hyperlipidemia, and cardiovascular disease has made it a major public health epidemic [1][2][3]. Energy components establish a balance between energy intake and expenditure [4,5].…”

Determination of the Maximal Lactate Steady State in Obese Zucker Rats

“…The determination of the intensity in the afore-mentioned studies is performed only by a progressive increase in velocity. Nam et al [ 15 ] investigated the eff ects of treadmill exercise in obese Zucker rats of 6 and 22 weeks of age using velocities at 16 m.min − 1 and 12 m.min − 1 , respectively. However, the protocol used for exercise training was the same as that for non-obese rats.…”