مجله دیابت و متابولیسم ایران
سال نوزدهم شماره 5 (پیاپی 93، خرداد و تیر 1399)

A novel nanocomposite-modified electrode based on reduced graphene oxide (rGO) decorated with crown-ether and gold nanoparticles (GNPs) on the surface of a glassy carbon electrode (GCE) was fabricated to investigate 5-HT determination.

The morphology of nanocomposite was characterized by scaning electron microscopy (SEM). Diabetic zebrafish was obtained by overfeeding via glucose. 5-HT was successfully determined in the presence of dopamine (DA), ascorbic acid (AA), urea, glucose, and L-tryptophan (L-Trp) by using electrochemical methods.

The nanocomposite exhibited satisfactory electrochemical catalytic activity for 5-HT determination using square-wave voltammetry (SWV). The electrochemical behavior of 5-HT at the nanocomposite/GCE displayed reasonable oxidation current and potential. The limit of detection (LOD) of 5-HT obtained from the real samples, containing the control and diabetic group by using the proposed system and HPLC method, was calculated to be about 0.3 and 0.1 µg/L, respectively. The prposed system also demonstrated high selectivity, reasonable sensitivity, and good stability and reproducibility for 5-HT sensing. The nanocomposite was applied for the determination of the biomarker 5-HT in the diabetic and control groups of zebrafish and displayed excellent recoveries about 93 and low relative error about 3% while compared with standard method.

It seems that the 5-HT level can be used for earlier diagnosis of diabetes.

One of the most important biological pathways involved in maintaining energy homeostasis is the AMPK PGC-1α pathway. Activation of this pathway through exercise can be important in regulating mitochondrial biogenesis processes and maintaining energy balance in diabetics. Therefore, the aim of this study was to investigate the effect of endurance exercise on the content of AMPK and PGC-1α proteins in the left ventricular heart tissue of male rats with type 2 diabetes.

In this experimental study, 12 two-month-old Sprague-Dawley rats with a mean weight of 270±20 g were selected. After diabetic induction with STZ and Nicotinamide, rats were randomly assigned to two groups, training diabetic and control diabetic (6 heads in group each). The training group performed 4 days a week for 8 weeks, including 30 minutes of endurance training with an intensity of about 50 to 70% of the maximum speed; While the control group did not have any training program. Also, rats did not receive any insulin treatment during the study period. The independent t-test was used in SPSS software version 21 to analyze the data.

A significant increase was observed in the content of AMPK (P=0.002) and PGC-1α (P=0.0001) proteins in the endurance exercise group compared to control.

Based on the results of the present study, endurance exercise was able to significantly increase the content of AMPK and PGC-1α proteins. Therefore, it is possible that an increasing these proteins can lead to energy production and increase mitochondrial biogenesis.

Diabetes and its oxidative stress increase the effects of this disease on heart tissue. On the other hand, exercise improves the antioxidant status of heart tissue. The aim of this study was to investigate the effect of 8 weeks of increased endurance training on superoxide dismutase activity and malondialdehyde levels in the heart tissue of mice with type 2 diabetes.

In this experimental study, 24 male Wistar rats (256 ±11.8 g, 10 weeks old) were divided into 4 groups of 6. Exercise program for 8 weeks of increasing endurance training. 48 h after completion of the protocol, the activity of superoxide dismutase enzyme and malondialdehyde levels in rat heart tissue were measured. One-way analysis of variance was used for group comparisons and Pearson test was used to examine the relationship between indicators.

There were significant difference between the four groups in superoxide dismutase (P= 0.001) and malondialdehyde (P= 0.001) indices. As a result of post-hoc test, there were significant increase in superoxide dismutase index in healthy exercise (P= 0.016) and control groups (P= 0.029) compared to diabetic control group and significant decrease in malondialdehyde index in control (P= 0.003), diabetic exercise (P= 0.050) and healthy exercise groups (P= 0.001) compared to diabetic control group. Significant correlation was observed between superoxide dismutase and malondialdehyde indices (r= 0.018, P= 0.274).

According to the results of this study, it seems that incremental endurance training reduces lipid peroxidation and improves antioxidant status and consequently reduces oxidative stress in cardiac tissue of diabetic rats.

The relationship between low PGC-1α expression and several metabolic diseases such as diabetes and obesity has been identified. This study investigates the effect of eight-week high intensity interval training (HIIT) and caffeine intake on mitochondrial biogenesis in soleus muscle in diabetic rats induced Streptozotocin.

In a clinical-interventional animal study, 50 male rats were randomly assigned to 5 equal groups (control group(C), diabetes group(D), diabetes + caffeine group(D+Caf), diabetes + training group(D+T), diabetes + training + caffeine group(D+CAF+T)) and subjected to 8 weeks of caffeine supplementation (70 mg / kg of caffeine powder was injected five days each week) and 8 weeks of 5 sessions per week with 6 to 12 times, 2-min intervals with intensity of 85-90% of maximal speed. Blood was collected directly from the left ventricle to measure blood glucose levels. The soleus muscle of the left leg was extracted and PGC-1α measured by Western Blot method. Independent t-tests, two-way analysis of variance, and Eta squared (p <0.05) were used to analyze the data.

The results showed that induction of diabetes significantly increased blood glucose (P <0.01) and significantly decreased mRNAPGC-1α (P = 0.002). Also, both high-intensity interval training (p = 0.001) and caffeine supplementation (p = 0.03) significantly increased mRNAPGC-1α.

Based on the results of this study, it is possible to suggest the use of HIIT and caffeine consumption as an effective intervention in increasing mitochondrial biogenesis in diabetics. However, a clear statement in this regard requires further research in this area.

The prevalence of type 2 diabetes is rapidly increasing in the world. As a result of this disease, long-term insulin resistance develops, as a result of which pancreatic beta cells are destroyed and disappear, as a result insulin is not released. Recently, a protein called lipasin, which is responsible for signaling the liver to beta cells, has been discovered, and previous reports have shown that lipasin/betatrophin increases pancreatic β cell proliferation. Therefore, the aim of this study was to investigate the effect of eight weeks of high intensity interval training (HIIT) and endurance training on lipasin gene expression in rats with type 2 diabetes.

The study was performed on 25 Wistar rats with a mean weight of 160±10 g and age of 8 weeks. After induction of diabetes, the rats were randomly divided into three groups of 6: control and endurance and HIIT. And exercise was performed for eight weeks (5 sessions per week). QRT-PCR technique was used to evaluate changes in hepatic lipasin gene expression.

The present study showed that after eight weeks of endurance training and HIIT, the expression of lipasin gene in the liver of rats in the training group increased significantly compared to the control group (P = 0.037); Also, a significant negative correlation was observed between lipasin gene expression and insulin resistance index in the exercise group compared to the control group (r = -0.605, P = 0.037).

It seems that performing eight weeks of endurance training and HIIT, by increasing the expression of lipasin gene can increase beta cells in diabetic patients and may be an effective non-pharmacological intervention to reduce the symptoms of this disease.

Although some studies have studied the mechanism of action of beta cells in animal models and more or less in human populations, but so far the role of exercise therapy or exercise exercise HIIT along with black grape supplementation on the expression of involved genes Less has been studied in pancreatic beta cells, so the aim of the present study was to investigate the effect of eight weeks of intense intermittent exercise with black grape supplementation on the expression of PPARα and PPARγ gene in pancreatic tissue of male rats with type 2 diabetes.

The study was conducted in the form of an experimental design. The subjects of this project were 40 8-month-old male rats with an average weight of 250 grams. After familiarizing the subjects with exercise and induction of diabetes by STZ, the subjects were randomly divided into 5 groups including exercise, supplement, exercise and supplement, diabetic control and basic control. After 8 weeks of training, 5 sessions per week for 8 weeks with 90% Vo2max activity and supplementation of black grape seed extract, PPARα and PPARγ genes were measured after RNA extraction from pancreas and cDNA synthesis. PPARα and PPARγ genes were measured by Time-Real PCR. Data were analyzed using independent t-test and two-factor analysis of variance at a significance level of 0.05 by SPSS software version 24.

The effect of exercise with consumption of black grape seed extract on the expression of PPARγ and PPARα genes in the pancreas of diabetic rats was not significant, but exercise alone significantly increased the expression of PPARα gene in the pancreatic tissue of diabetic specimens. Consumption of black grape seed extract alone significantly increased the expression of PPARγ and PPARα genes.

It seems that regulating the expression of PPARα and PPARγ genes through exercise and consumption of black grape seed extract may lead to the improvement and maintenance of pancreatic beta cell function in diabetic rats.