Serum, liver, and kidney proteomic analysis for the alloxan-induced type I diabetic mice after insulin gene transfer of naked plasmid through electroporation

Trigonella foenum-graecum seeds extract plays a beneficial role on brain antioxidant and oxidative status in alloxan-induced Wistar rats

Context

Trigonella foenum-graecum (TriFG) exhibits increased scavenger enzymatic activities and reduces the production of reactive oxygen species in diabetic rats.

Objective

The present study was aimed to investigate the effect of TriFG on lipid peroxidation levels and antioxidant status in brain tissue of rats exposed to alloxan.

Materials and Methods

Healthy male rats (180 ± 10 g) were allocated into five groups. Animals in group 1 maintained on normal tap water served as controls and rats in groups 2, 3, 4, and 5 were treated as experimental groups. Rats in group 2 were intraperitoneally injected with alloxan (120 mg/kg BW) and treated as diabetic rats, whereas rats in groups 3 and 4 were maintained on same experimental regimen as that of rats in groups 1 and 2, respectively, and in addition, they were orally gavaged with herbal extracts of TriFG (0.25 g/kg BW). Diabetic rats treated with glibenclamide in group 5 were used as positive controls.

Results and Discussion

Significant (P < 0.001) increase in the antioxidant enzymes with a significant (P < 0.001) decrease in the lipid peroxidation levels were observed in the brain tissue of diabetic rats treated with TriFG extract as compared to diabetic and glibenclamide-treated rats. No significant changes were observed in pro- and antioxidant levels in brain tissue of rats treated with TriFG extract alone when compared to normal rats. In diabetic rats, brain mitochondrial and cytosolic enzymes like succinate dehydrogenase, glutamate dehydrogenase, and glucose-6-phosphate dehydrogenase activity levels were significantly (P < 0.05) decreased with reversely increased was observed in lactate dehydrogenase activity (P < 0.05).

Conclusions

The findings of the present study suggested that TriFG, through its antioxidant properties, protects brain tissue by mitigating oxidative stress induced by alloxan-exposed rats. TriFG extract significantly increased the antioxidant and oxidative properties in diabetic rats when compared with the control group rats.

Quantitative mass spectrometry of diabetic kidney tubules identifies GRAP as a novel regulator of TGF-beta signaling

The aim of this study was to define novel mediators of tubule injury in diabetic kidney disease. For this, we used state-of-the-art proteomic methods combined with a label-free quantitative strategy to define protein expression differences in kidney tubules from transgenic OVE26 type 1 diabetic and control mice. The analysis was performed with diabetic samples that displayed a pro-fibrotic phenotype. We have identified 476 differentially expressed proteins. Bioinformatic analysis indicated several clusters of regulated proteins in relevant functional groups such as TGF-beta signaling, tight junction maintenance, oxidative stress, and glucose metabolism. Mass spectrometry detected expression changes of four physiologically relevant proteins were confirmed by immunoblot analysis. Of these, the Grb2-related adaptor protein (GRAP) was up-regulated in kidney tubules from diabetic mice and fibrotic kidneys from diabetic patients, and subsequently confirmed as a novel component of TGF-beta signaling in cultured human renal tubule cells. Thus, indicating a potential novel role for GRAP in TGF-beta-induced tubule injury in diabetic kidney disease. Although we targeted a specific disease, this approach offers a robust, high-sensitivity methodology that can be applied to the discovery of novel mediators for any experimental or disease condition.

Proteomic studies in animal models of diabetes

The aim of this review is to provide an overview of proteomic studies in animal models of diabetes and to give some insight into the different methods available today in the rapidly developing field of proteomics. A summary of 31 papers published between 1997 and 2007 is presented. For instance, proteomics has been used to study the development of both type 1 and type 2 diabetes, diabetic complications in tissues like heart, kidney and retina and changes after treatment with anti-diabetic drugs like peroxisome proliferator-activated receptors agonists. Together, these studies give a good overview of a number of experimental approaches. Proteomics holds the promise of providing major contributions to the field of diabetes research. However, to achieve this, a number of issues need to be resolved. Appropriate data representation to facilitate data comparison, exchange, and verification is required, as well as improved statistical assessment of proteomic experiments. In addition, it is important to follow up the results with functional studies to be able to make biologically relevant conclusions. The potential of proteomics to dissect complex human disorders is now beginning to be realized. In the future, this will result in new important information concerning diabetes.

Proteomics and diabetic nephropathy

Proteomic methods have found broad applications in kidney disease research and more specifically in diabetic nephropathy (DN) research. Proteomic methods such as 2-dimensional gel electrophoresis have been used to gain insight into glomerular and tubular nephropathies including DN. At the protein level, differences in high-abundant proteins in DN have been shown to reflect primarily differentially posttranslationally modified plasma proteins. Higher-sensitivity proteomic methods (eg, liquid chromatography-mass spectrometry) have pushed the boundaries on the known urinary proteome to include more than 1,500 proteins. These same high-sensitivity methods have been applied toward profiling urinary peptides, which has resulted in methods to diagnostically screen urine to differentiate between type-2 diabetes mellitus and type-1 diabetes mellitus urine, normal versus microalbuminuria, or by angiotensin II receptor blocker treatment. Proteomic methods are being used to show response to insulin gene therapy in an animal model or alterations in the renal cortex mitochondrial proteome with the development of the diabetic phenotype. Proteomic methods continue to aid in the discovery of new mechanisms of diabetic pathology and understanding of the etiology of diabetic complications.