Diazoxide and moderate-intensity exercise improve skeletal muscle function by decreasing oxidants and enhancing antioxidant defenses in hypertensive male rats.

High sodium intake is decisive in the incidence increase and prevalence of hypertension, which has an impact on skeletal muscle functionality. Diazoxide is an antihypertensive agent that inhibits insulin secretion and is an opener of KATP channels (adosine triphosphate sensitive potasium channels). For this reason, it is hypothesized that moderate-intensity exercise and diazoxide improve skeletal muscle function by reducing the oxidants in hypertensive rats. Male Wistar rats were assigned into eight groups: control (CTRL), diazoxide (DZX), exercise (EX), exercise + diazoxide (EX + DZX), hypertension (HTN), hypertension + diazoxide (HTN + DZX), hypertension + exercise (HTN + EX), and hypertension + exercise + diazoxide (HTN + EX + DZX). To induce hypertension, the rats received 8% NaCl dissolved in water orally for 30 days; in the following 8 weeks, 4% NaCl was supplied to maintain the pathology. The treatment with physical exercise of moderate intensity lasted 8 weeks. The administration dose of diazoxide was 35 mg/kg intraperitoneally for 14 days. Tension recording was performed on the extensor digitorum longus and the soleus muscle. Muscle homogenates were used to measure oxidants using fluorescent probe and the activity of antioxidant systems. Diazoxide and moderate-intensity exercise reduced oxidants and increased antioxidant defenses.

Diazoxide improves muscle function in association with improved dyslipidemia and decreased muscle oxidative stress in streptozotocin-induced diabetic rats.

AIM/INTRODUCTION: Diabetes Mellitus is a chronic degenerative disease, and its main biochemical characteristic is hyperglycemia due to impaired insulin secretion, resistance to peripheral actions of insulin, or both. Hyperglycemia causes dyslipidemia and stimulates oxidative damage, leading to the main symptoms, such as fatigue and culminates in diabetic complications. Previous studies have shown that ATP-sensitive potassium channels counteract muscle fatigue and metabolic stress in healthy mouse models. To determine the effect of diazoxide on muscle strength development during diabetes, we tested the effect of diazoxide in streptozotocin-diabetic rats in muscle function, lipid profile and oxidative stress biomarkers. MATERIALS AND METHODS: Wistar rats were divided into 4 groups of six animals each: (1) Control group, (2) diabetes group, (3) Control group + diazoxide, and (4) Diabetic + diazoxide (DB + DZX). 4 weeks after rats were sacrificed, soleus and extensor digitorum longus muscles (EDL) were extracted to prepare homogenates and serum was obtained for biochemical measurements. Oxidative damage was evaluated by the thiobarbituric acid method and the fluorescent for reactive oxygen species (ROS) probe 2,4-H2DCFDA, respectively. RESULTS: Diabetic rats with diazoxide administration showed an increase in the development of muscle strength in both muscles; in turn, the onset of fatigue was longer compared to the group of diabetic rats without treatment. Regarding the lipid profile, diazoxide decreased total cholesterol levels in the group of diabetic rats treated with diazoxide (x̅46.2 mg/dL) compared to the untreated diabetic group (x̅=104.4 mg/dL); secondly, diazoxide decreased triglyceride concentrations (x̅=105.3 mg/dL) compared to the untreated diabetic rats (x̅=412.2 mg/dL) as well as the levels of very low-density lipoproteins (x̅=20.4 mg/dL vs. x̅=82.44 mg/dL). Regarding the various markers of oxidative stress, the diabetic group treated with diazoxide was able to reduce the concentrations of TBARS and total reactive oxygen species as well as preserve the concentrations of reduced glutathione. CONCLUSION: Diazoxide administration in diabetic rats increases muscle strength development in EDL and soleus muscle, decreases fatigue, reduces cholesterol and triglyceride concentrations and improves oxidative stress parameters such as TBARS, ROS, and glutathione status.

Comparative Effect of Three Different Exercise Intensities in Combination with Diazoxide on Contraction Capacity and Oxidative Stress of Skeletal Muscle in Obese Rats.

Obesity is a chronic disease that impairs skeletal muscle function, affects the ability to contract, and promotes the development of fatigue. For this reason, the study of treatments that seek to reduce the harmful effects of obesity on muscle tissue has been deepened. Diazoxide treatment and various exercise protocols have been proposed to protect skeletal muscle against oxidative stress and its effects. However, the intensity and duration of exercise combined with diazoxide that would obtain the best results for improving skeletal muscle function in obese rats is unknown. To this end, this study evaluated the effects of three different exercise intensities combined with diazoxide on contraction capacity, resistance to fatigue, markers of oxidative stress, lipid peroxidation, ROS, and glutathione redox status of skeletal muscle. The results showed that treatments with diazoxide and exercise at different intensities improved muscle contraction capacity by reducing oxidative stress during obesity, with the best results being obtained with low-intensity exercise in combination with diazoxide. Therefore, these results suggest that diazoxide and low-intensity exercise improve muscle function during obesity by decreasing oxidative stress with the same efficiency as a moderate-intensity exercise protocol.

Dietary Iron Restriction Improves Muscle Function, Dyslipidemia, and Decreased Muscle Oxidative Stress in Streptozotocin-Induced Diabetic Rats.

Diabetes mellitus is a chronic degenerative disease characterized by hyperglycemia and oxidative stress. Iron catalyzes free radical overproduction. High iron concentrations have previously been reported to promote an increase in oxidative stress; however, the effect of iron restriction in diabetes has not yet been explored, so we tested to see if iron restriction in diabetic rats reduces oxidative damage and improved muscle function. Wistar rats were assigned to 4 groups: Control; Diabetic; Diabetic rats with a high iron diet, and Diabetic with dietary iron restriction. After 8 weeks the rats were sacrificed, the muscles were extracted to prepare homogenates, and serum was obtained for biochemical measurements. Low iron diabetic rats showed an increase in the development of muscle strength in both muscles. Dietary iron restriction decreased triglyceride concentrations compared to the untreated diabetic rats and the levels of extremely low-density lipoproteins. Aggravation of lipid peroxidation was observed in the diabetic group with a high iron diet, while these levels remained low with iron restriction. Iron restriction improved muscle strength development and reduced fatigue times; this was related to better lipid profile control and decreased oxidant stress markers.

Healing of Wounds Treated with Chitosan Hydrogels with Extracts from Aloe vera and Calendula officinalis / Cicatrización de Heridas Tratadas con Hidrogeles de Quitosano con Extractos de Aloe vera y Calendula officinalis

ABSTRACT This project's purpose was to evaluate the healing effects of chitosan (CS) hydrogels loaded with extracts from Aloe vera (CS+AV) and Calendula officinalis (CS+CO) on wounds of diabetic and non-diabetic Wistar rats. A total of 24 rats were used; animals were randomly divided into three diabetic and three non-diabetic groups (one control and two treated groups) and monitored for 13 days. A biopsy on the wound site was recovered to assess the collagen and n-acetyl glucosamine content. The wound area ratio was reduced since day 1 on both non-diabetic treated groups. A similar effect was observed on the diabetic group treated with CS+AV, while the diabetic group treated with CS+CO showed a reduction in wound area compared to the diabetic control until day 11 after being wounded. Collagen and n-acetyl glucosamine content were higher in every treated group. Further studies are needed to clarify the underlying mechanisms through which they promote wound healing. These results suggest that the hydrogels prepared are potential material to be used as wound dressings.

RESUMEN El propósito de este proyecto fue evaluar los efectos curativos de los hidrogeles de quitosano con extractos de Aloe vera (CS + AV) y Calendula officinalis (CS + CO) en heridas en ratas Wistar diabéticas y no diabéticas. Se utilizaron un total de 24 ratas; los animales fueron divididos aleatoriamente en tres grupos diabéticos y tres no diabéticos (un grupo control y dos tratados) y se monitorearon durante 13 días. Se recuperó una biopsia del sitio de la herida para evaluar el contenido de colágeno y n-acetilglucosamina. El área de la herida se redujo desde el día 1 en ambos grupos no diabéticos tratados. Se observó un efecto similar en el grupo diabético tratado con CS + AV, mientras que el grupo diabético tratado con CS + CO mostró una reducción del área de la herida en comparación al control diabético hasta el día 11 después de la creación de la herida. El contenido de colágeno y n-acetilglucosamina fue mayor en todos los grupos tratados. Se necesitan más estudios para aclarar los mecanismos subyacentes a través de los cuales estos tratamientos promueven la cicatrización de heridas. Estos resultados sugieren que los hidrogeles preparados son materiales con potencial para usarse como apósitos para heridas.

Diazoxide and Exercise Enhance Muscle Contraction during Obesity by Decreasing ROS Levels, Lipid Peroxidation, and Improving Glutathione Redox Status.

Obesity causes insulin resistance and hyperinsulinemia which causes skeletal muscle dysfunction resulting in a decrease in contraction force and a reduced capacity to avoid fatigue, which overall, causes an increase in oxidative stress. KATP channel openers such as diazoxide and the implementation of exercise protocols have been reported to be actively involved in protecting skeletal muscle against metabolic stress; however, the effects of diazoxide and exercise on muscle contraction and oxidative stress during obesity have not been explored. This study aimed to determine the effect of diazoxide in the contraction of skeletal muscle of obese male Wistar rats (35 mg/kg), and with an exercise protocol (five weeks) and the combination from both. Results showed that the treatment with diazoxide and exercise improved muscular contraction, showing an increase in maximum tension and total tension due to decreased ROS and lipid peroxidation levels and improved glutathione redox state. Therefore, these results suggest that diazoxide and exercise improve muscle function during obesity, possibly through its effects as KATP channel openers.