Effect of Physical Exercise and Genetic Background on Glucose Homeostasis and Liver/Muscle Proteomes in Mice.

We compared the parameters related to glucose homeostasis, and liver and muscle proteomes in fluorosis-susceptible (A/J; S) and fluorosis-resistant (129P3/J; R) mice in response to fluoride (F) exposure and exercise. Ninety male mice (45 R-mice and 45 S-mice) were randomized into three groups: (SI; RI) No-F, No-Exercise, (SII; RII) 50 ppm F, No-Exercise, (SIII; RIII) 50 ppm F, Exercise. Overall, mean F concentrations in the plasma and femur were significantly higher in R-mice compared with S-mice. In R-mice, exercise resulted in an increase in F accumulation in the femur. In S-mice, the mean plasma glucose level was significantly higher in Group II compared with Groups I and III. There was an increase in liver proteins involved in energy flux and antioxidant enzymes in non-exercise groups (I, II) of S-mice in comparison with the corresponding groups of R-mice. The results also showed a decrease in muscle protein expression in Group I S-mice compared with their R-mice counterparts. In conclusion, the findings suggest an increased state of oxidative stress in fluorosis-susceptible mice that might be exacerbated by the treatment with F. In addition, fluorosis-susceptible mice have plasma glucose levels higher than fluorosis-resistant mice on exposure to F, and this is not affected by exercise.

Standardization of a new non-invasive device for assessment of arterial stiffness in rats: Correlation with age-related arteries' structure.

Pulse wave velocity (PWV) has become a gold standard index to quantify the stiffness of the aorta and is a predictor of cardiovascular events. A recent paper compared the pOpmètreⓇ, a device for measuring the finger-toe PWV, with other techniques and demonstrated its accuracy and validity. However, human devices do not allow the advancement of our knowledge on conditioning mechanisms. Based on its human validation, a new device, pOpetⓇ 1.0 system was designed for estimation of PWV in small animals and this present study aimed to standardize the pOpetⓇ 1.0 for estimation of arterial stiffness in rats, and to confirm its liability and stability as well as the reproducibility of assessments. Therefore several precautions were taken into consideration like as the correct position of the animal and photodiodes according to manufacturers' suggestions. Results indicated that estimation of PWV through the new pOpetⓇ 1.0 device exhibits good internal consistency, stability and objectivity in all tests performed between days and evaluators. Importantly, data suggest for the first time that this new device is able to detect changes in arterial stiffness that are conditioned by age and pressure-related arterial remodeling. • This new pOpetⓇ device is able to detect changes in vessel structure. • This new pOpetⓇ device exhibits good internal consistency, stability and objectivity in all tests performed • Correct position of the animal and photodiodes are crucial to obtain a very stable signal.

Short-term exposure to dexamethasone promotes autonomic imbalance to the heart before hypertension.

Hypertension is one of the chronic side effects of dexamethasone (DEX) treatment; however, almost nothing is known about its acute effects. Therefore, the aim of this study was to investigate the possible mechanisms involved in blood pressure control after acute or short-term DEX treatment in adult animals. Eighty Wistar rats were divided into four groups: C1 and C5, for rats treated with saline for 1 or 5 days, respectively; D1 and D5, for rats treated with DEX for 1 or 5 days, respectively (decadron, 1 mg/kg, i.p.). Heart rate was increased in DEX treatment, but arterial pressure and cardiac muscle mass were not altered. Only few and isolated changes on gene expression and protein level of renin-angiotensin system components were observed. Five days of DEX treatment, but not one day, determined an increase in sympathetic component of spectral analysis (+75.93%, P < .05) and a significant reduction of parasympathetic component (-18.02%, P < .05), which contributed to the autonomic imbalance to the heart (LF/HF, +863.69%). The results of this present study demonstrated, for the first time, that short-term exposure to DEX treatment impairs the autonomic balance to the heart before hypertension, which was independent of renin-angiotensin system.

Effect of chronic exercise on fluoride metabolism in fluorosis-susceptible mice exposed to high fluoride.

The present study investigated the effect of chronic exercise on fluoride (F) metabolism in fluorosis-susceptible mice exposed to high-F and explored the relationship between F concentrations in bone and plasma. Thirty male mice were randomised into three groups: Group I (No-F, No-Exercise), Group II (50 ppmF, No-Exercise), Group III (50 ppmF, Exercise). Body weight and physical performance of all mice were measured at baseline and end of experiment. F concentrations of plasma and bone were measured at the end of experiment. Mean plasma F concentration was significantly higher (p < 0.001) in Groups II and III compared with Group I. Mean bone F concentration was also significantly higher (p < 0.01) in Groups II and III compared with Group I. There was a significant correlation (p = 0.01, r = 0.54) between F concentration of plasma and bone. Mean body weight of Group I mice was significantly higher than Group II (p < 0.001) and Group III (p = 0.001) mice at the end of the experiment. This study, which provides the first data on the effect of chronic exercise on F metabolism in fluorosis-susceptible mice, suggests no effect of chronic exercise on F in plasma and bone. However, exposure to high-F resulted in lower body weight and exercise capacity in mice.