Effects Of Voluntary Wheel Running Research Articles

THE EFFECT OF VOLUNTARY WHEEL EXERCISE AND STRESS ON THE SPECIFIC ANTIBODY ANTIBODY RESPONSE

121 Stressor modulates immune function, such that innate immune function is potentiated and adaptive (specific) immune function is suppressed. Acute stress suppresses the in vivo development of the specific antibody response. Voluntary exercise may buffer stress effects. Thus, we investigated the effect of voluntary wheel running on the stress-induced suppression of the specific antibody response. Each experiment (10/grp) contained 1). Exercise + stress, 2) Exercise + no stress, 3) Sedentary + stress, 3) Sedentary + no stress. Stress was exposure to tail shock (100, 5-s, 1.6mA, ave. ITI-60-s). Adult male Sprague-Dawley rats lived in cages with attached running wheels. Sedentary controls lived in identical cages, except the wheel was rendered inactive. In vivo specific immune function was assessed by immunizing the rats intraperitoneally with a benign soluble protein, keyhole limpet hemocyanin or KLH (200μg). Weekly blood samples were taken from the tail vein and serum anti-KLH IgM and IgG were measured using ELISA. Exp. 1-Rats were immunized with KLH and exposed to stress or remained in their home cage. Immediately after stress termination, rats were returned to their running wheel cages and allowed to run for 6 weeks. Exp. 2-This study was conducted just as exp. 1 except rats were allowed to live with running wheels (half active and half inactive) prior to exposure to stress. After 6 weeks, rats were immunized with KLH and exposed to stress or remained in their home cage. Blood samples were taken weekly for 6 weeks after KLH. The results from exp. 1 were that voluntary wheel running after stress exposure prevented the stress-induced suppression in anti-KLH IgM and IgG. Weekly average distance run was reduced by stress. The results from exp. 2 are not yet available. These data support to the hypothesis that voluntary activity protects against stress-induced immunosuppression.

Beneficial effects of voluntary wheel running on the properties of dystrophic mouse muscle.

Effects of voluntary exercise on the isometric contractile, fatigue, and histochemical properties of hindlimb dystrophic (mdx and 129ReJ dy/dy) skeletal muscles were investigated. Mice were allowed free access to a voluntary running wheel at 4 wk of age for a duration of 16 (mdx) or 5 (dy/dy) wk. Running performance of mdx mice (approximately 4 km/day at 1.6 km/h) was inferior to normal mice (approximately 6.5 km/day at 2.1 km/h). However, exercise improved the force output (approximately 15%) and the fatigue resistance of both C57BL/10 and mdx soleus muscles. These changes coincided with increased proportions of smaller type I fibers and decreased proportions of larger type IIa fibers in the mdx soleus. The extensor digitorum longus of mdx, but not of normal, mice also exhibited improved resistance to fatigue and conversion towards oxidative fiber types. The dy/dy animals were capable of exercising, yet ran significantly less than normal animals (approximately 0.5 km/day). Despite this, running increased the force output of the plantaris muscle (approximately 50%). Taken together, the results showed that exercise can have beneficial effects on dystrophic skeletal muscles.

Aspirin delays hyperthermia-induced platelet aggregation in pial microvessels of the mouse

Ethanol withdrawal is a dysphoric condition that arises from termination of ethanol intake by dependent individuals. Common withdrawal symptoms include anxiety, increased reactivity to stimuli and increased seizure susceptibility as well as the risk of increased seizure severity. We use an animal model of dependence and withdrawal to study withdrawal behaviors and potential underlying neurobiological mechanisms. For a number of years, we have quantified pentylenetetrazol seizure thresholds as an assessment of ethanol withdrawal at both one day and three days of withdrawal. Typically, we see a significant decrease in seizure threshold (increased sensitivity to seizure induction) that persists through three days of withdrawal for male rats. Increasing evidence indicates that voluntary exercise affords protection against various challenges to physical and psychological health, including ethanol-related challenges. Therefore, the current study investigated the effect of voluntary wheel running on seizure susceptibility following chronic ethanol administration and withdrawal. We found that voluntary wheel running attenuated the increased sensitivity to pentylenetetrazol-induced seizures observed with ethanol withdrawal, at both the one-day and three-day time points. This result was especially interesting as animals with access to the running wheels consumed more of the ethanol-containing diet. These findings showed that chronic voluntary wheel running reduces the severity of ethanol withdrawal in our animal model and suggest that exercise-based interventions may have some utility in the clinical management of heavy drinking and alcohol withdrawal.

Effects of voluntary wheel running on health indexes in rats with SRBC-induced inflammation

The effects of voluntary running exercise on health indexes in rats were studied before and after Sheep Red Blood Cell (SRBC)-induced inflammation. Male Fischer rats (SPF) 8 weeks of age were housed in individual sedentary cages (sedentary group) or in individual wheel-running cages (exercise group) for 4 months. Then all rats were injected with 20% SRBC (0.5 ml/100g body weight) i.p. Voluntary running activity averaged 1408m/day, reached a peak (2913m/day) at the 25th day and waned over time, reaching a plateau at the 60th day (about 1000m/day). In spite of a significant increase in food intake (117%), exercising rats gained significantly less weight (93%) than sedentary rats at all times in experimental period. The exercise group also showed a significant decrease in the value of serum triglyceride (TG) and total cholesterol (T. CHO) (TG p < 0.0002, T. CHO p < 0.03). The hematocrit (Ht) and hemoglobin concentration (Hb) were higher in the exercised rats, and at 4 days after i.p. SRBC, the difference became statistically significant (Ht p < 0.0002, Hb p < 0.003). Thus, protective effects against the decrease of Ht and Hb were demonstrated in the exercised group. Perhaps this inflammation did not impair liver function severely; sedentary rats had normal or slightly higher levels of GOT and GPT. On the other hand, exercised rats had lower GOT and GPT. Significant differences were found between the groups (GOT, GPT p < 0.0001).

Effects of voluntary exercise on immune function in rats

We investigated effects of voluntary wheel running on specific antibody responses to Keyhole Limpet Hemocyanin (KLH) and on mitogen-stimulated lymphocyte proliferation in adult male rats. Each subject was placed in a running wheel for 12 h daily during the dark portion of the light cycle for a total of 8 weeks. For experimental animals the wheels rotated freely, enabling subjects to exercise at will, while for control animals the wheels were prevented from rotating. Subjects were immunized with KLH (25 μg) 5 weeks into the study, and blood samples were collected intermittently from the tail for 3 weeks and later assayed for anti-KLH antibody levels. At the end of the study, subjects were sacrificed and spleens were dissected and assayed for lymphocyte proliferative responses to the mitogen Concanavalin A. Exercised rats gained less weight and had higher splenic proliferative responses than control rats; however, there were no significant group differences in anti-KLH antibody levels.

Exercise and Food Restriction in Rats ,

A number of studies have shown that exercised rats live longer than sedentary freely eating controls. There is disagreement regarding whether exercise results in extension of maximal life span. However, in two studies of the effect of voluntary wheel running on longevity of male specific-pathogen-free Long-Evans rats it was found that, although the runners had a longer average survival than sedentary freely eating controls, they did not have an increase in maximal life span. This is in contrast to the effect of food restriction. Sedentary rats that were food restricted to keep their body weights in the same range as those of the runners lived longer than the runners and showed an extension of life span. When exercise, in the form of voluntary wheel running was combined with food restriction (∼30% below ad libitum), the runners had an increased mortality rate over the first ∼50% of their mortality curve up to age ∼900 d. However, in those food-restricted runners that survived past ∼900 d survival became similar to that of food-restricted sedentary controls, with a similar increase in maximal life span. Thus, although exercise has a deleterious effect on food-restricted rats, it does not counteract the increase in maximal life span induced by food restriction.