Protective effects of Moutan Cortex polysaccharides components on renal injury in diabetic nephropathy rats / 中国中药杂志

This study investigated the protective effects of Moutan Cortex polysaccharides components(MCPC) on the renal tissues of diabetic nephropathy(DN) rats and explored their regulation effect on inflammatory response and oxidative stress. The DN rat model was induced by high-glucose and high-fat diet combined with streptozotocin(STZ), and then the rats were randomly divided into control group, model group, positive group and MCPC high(120 mg·kg~(-1)·d~(-1)), low(60 mg·kg~(-1)·d~(-1)) dose groups. After 12 weeks treatment, blood was taken from the orbit of the rats, and then they were sacrificed before the kidney tissues were collected. The serum and tissues were detected for related biochemical indicators and pathological changes of the kidney. Immunohistochemical methods were used to determine the expression of FN and ColⅣ in the kidney tissue of DN rats. Compared with the model group, blood glucose, serum creatinine, blood urea nitrogen and 24 h urine protein in the MCPC high-dose group were significantly reduced(P<0.01). The results of HE, PAS, Masson staining showed that glomerular basement membrane thickening, Bowman's capsule narrowing and inflammatory cell infiltration in DN rats were improved in the MCPC high-dose group; the activity of T-SOD and GSH-Px in serum significantly increased(P<0.001), and the expression level of FN significantly decreased(P<0.001). The high-dose MCPC treatment could effectively inhibit the abnormal expression of Col Ⅳ(P<0.001) and significantly reduce the levels of AGEs and RAGE in serum(P<0.001), the content of VCAM-1 and IL-1β in serum(P<0.001), and the levels of IL-1β mRNA in kidney tissue(P<0.001), but failed to effectively reduce VCAM-1 mRNA levels in kidney tissues. The high-dose MCPC could significantly improve pathological injury of renal tissue and related renal indicators in DN rats, and achieve renal protection in DN rats mainly by regulating oxidative stress and inflammatory factors.

Molecular mechanism of Gegen Qinlian Decoction in promoting differentiation of brown adipose tissue to improve glucose and lipid metabolism disorders in diabetic rats / 中国中药杂志

This study explored the molecular mechanism underlying the Gegen Qinlian Decoction(GQD) promoting the differentiation of brown adipose tissue(BAT) to improve glucose and lipid metabolism disorders in diabetic rats. After the hypoglycemic effect of GQD on diabetic rats induced by high-fat diet combined with a low dose of streptozotocin was confirmed, the total RNA of rat BAT around scapula was extracted. Nuclear transcription genes Prdm16, Pparγc1α, Pparα, Pparγ and Sirt1, BAT marker genes Ucp1, Cidea and Dio2, energy expenditure gene Ampkα2 as well as BAT secretion factors Adpn, Fndc5, Angptl8, IL-6 and Rbp4 were detected by qPCR, then were analyzed by IPA software. Afterward, the total protein from rat BAT was extracted, and PRDM16, PGC1α, PPARγ, PPARα, SIRT1, ChREBP, AMPKα, UCP1, ADPN, NRG4, GLUT1 and GLUT4 were detected by Western blot. The mRNA expression levels of Pparγc1α, Pparα, Pparγ, Ucp1, Cidea, Ampkα2, Dio2, Fndc5, Rbp4 and Angptl8 were significantly increased(P<0.05) and those of Adpn and IL-6 were significantly decreased(P<0.05) in the GQD group compared with the diabetic group. In addition, Sirt1 showed a downward trend(P=0.104), whereas Prdm16 tended to be up-regulated(P=0.182) in the GQD group. IPA canonical pathway analysis and diseases-and-functions analysis suggested that GQD activated PPARα/RXRα and SIRT1 signaling pathways to promote the differentiation of BAT and reduce the excessive lipid accumulation. Moreover, the protein expression levels of PRDM16, PGC1α, PPARα, PPARγ, SIRT1, ChREBP, AMPKα, UCP1, GLUT1, GLUT4 and NRG4 were significantly decreased in the diabetic group(P<0.01), which were elevated after GQD intervention(P<0.05). Unexpectedly, the expression of ADPN protein in the diabetic group was up-regulated(P<0.01) as compared with the control group, which was down-regulated after the administration with GQD(P<0.01). This study indicated that GQD promoted BAT differentiation and maturity to increase energy consumption, which reduced the glucose and lipid metabolism disorders and thereby improved diabetes symptoms.

Expression profile of mitrogen-activated protein kinase (MAPK) signaling genes in the skeletal muscle & liver of rat with type 2 diabetes: Role in disease pathology.

Background & objectives: Type 2 diabetes (T2D) is characterized as hyperglycaemia caused by defects in insulin secretion, and it affects target tissues, such as skeletal muscle, liver and adipose tissue. Therefore, analyzing the changes of gene expression profiles in these tissues is important to elucidate the pathogenesis of T2D. We, therefore, measured the gene transcript alterations in liver and skeletal muscle of rat with induced T2D, to detect differentially expressed genes in liver and skeletal muscle and perform gene-annotation enrichment analysis. Methods: In the present study, skeletal muscle and liver tissue from 10 streptozotocin-induced diabetic rats and 10 control rats were analyzed using gene expression microarrays. KEGG pathways enriched by differentially expressed genes (DEGs) were identified by WebGestalt Expander and GATHER software. DEGs were validated by the method of real-time PCR and western blot. Results: From the 9,929 expressed genes across the genome, 1,305 and 997 differentially expressed genes (DEGs, P<0.01) were identified in comparisons of skeletal muscle and liver, respectively. large numbers of DEGs (200) were common in both comparisons, which was clearly more than the predicted number (131 genes, P<0.001). For further interpretation of the gene expression data, three over-representation analysis softwares (WebGestalt, Expander and GATHER) were used. All the tools detected one KEGG pathway (MAPK signaling) and two GO (gene ontology) biological processes (response to stress and cell death), with enrichment of DEGs in both tissues. In addition, PPI (protein-protein interaction) networks constructed using human homologues not only revealed the tendency of DEGs to form a highly connected module, but also suggested a “hub” role of p38-MAPK-related genes (such as MAPK14) in the pathogenesis of T2D. Interpretation & conclusions: Our results indicated the considerably aberrant MAPK signaling in both insulin-sensitive tissues of T2D rat, and that the p38 may play a role as a common “hub” in the gene module response to hyperglycaemia. Furthermore, our research pinpoints the role of several new T2D-associated genes (such as Srebf1 and Ppargc1) in the human population.

Modificaciones dinámicas en los islotes de Langerhans de dos Líneas de ratas espontaneamente diabeticas / Dynamic modifications in islets of Langerhans in two lines of spontaneously diabetic rats

La rata eSMT derivó del cruzamiento de eSS y b, líneas de la cepa IIM. eSS es un modelo de diabetes tipo 2 sin sobrepeso; b desarrolla obesidad moderada e intolerancia tardía a la glucosa. Fueron comparados características metabólicas y hallazgos histopatológicos del páncreas endocrino entre eSS y eSMT. Cotejados con eSS, los animales eSMT jóvenes son más corpulentos y desarrollan hiperglucemia de ayuno e intolerancia a la glucosa más precoces e intensas. En los machos eSMT de 6 y 9 meses existen islotes de formas alteradas y con fibrosis, detectándose esporádicas imágenes de apoptosis. En los de un año se tornan más pequeños y escasos, remedando la histoarquitectura de los machos eSS en el segundo año de vida; posteriormente los islotes van disgregándose, a la vez que muestran ocasionales mitosis y se observa nesidioblastosis. Se sugiere que estas modificaciones dinámicas constituyen una respuesta a la hiperglucemia. Las hembras eSS conservan por más tiempo la estructura insular y tienen menores alteraciones de la glucemia. El dimorfismo sexual del síndrome diabético de eSMT es atenuado respecto de eSS. La construcción de una tipología de individuos mediante el análisis multivariado separó tres clusters, evidenciando diferencias genéticas, etáreas y de sexo.

The eSMT rat is derived from the crossing of eSS and b, both lines belonging to the IIM strain, while eSS is a model of type 2 diabetes without overweight and b develops moderate obesity and late glucose intolerance. Metabolic characteristics and histopathological findings in endocrine pancreas of eSS and eSMT were compared. Young eSMT animals are more robust than eSS and develop more intense fasting hyperglycemia and glucose intolerance at an earlier age. eSMT males of 6 and 9 months show islets with altered shapes and fibrosis, as well as sporadic images of apoptosis. At 12 months of age, islets are reduced in number and size, resembling the histoarchitecture of eSS males during their second year of life; eventually islets undergo disruption and, at the same time, occasional mitoses and nesidioblastosis are seen. These dynamic modifications may be expressing a response to hyperglycemia. eSS females preserve their insular structure for a longer time and have less glycemic alterations. Sexual dimorphism of the diabetic syndrome of eSMT is attenuated when compared with eSS. The construction of a typology of individuals through multivariate analysis separated three clusters, evidencing genetic, age and sex differences.

Animal models in type 2 diabetes research: an overview.

Type 2 diabetes is a complex and heterogeneous disorder presently affecting more than 100 million people worldwide and causing serious socio-economic problems. Appropriate experimental models are essential tools for understanding the pathogenesis, complications, and genetic or environmental influences that increase the risks of type 2 diabetes and testing of various therapeutic agents. The animal models of type 2 diabetes can be obtained either spontaneously or induced by chemicals or dietary or surgical manipulations and/or by combination thereof. In recent years, large number of new genetically modified animal models including transgenic, generalized knock-out and tissue-specific knockout mice have been engineered for the study of diabetes. This review gives an overview on the animal models of type 2 diabetes with reference to their origin/source, characteristic features, underlying causes/mechanism(s), advantages and disadvantages to the investigators in diabetes research. In addition, it especially describes the appropriate selection and usefulness of different animal models in preclinical testing of various new chemical entities (NCEs) for the treatment of type 2 diabetes.

Microarray for Genes Associated with Signal Transduction in Diabetic OLETF Keratocytes

PURPOSE: The purpose of this study was to identify differences in signal transduction gene expression between normal and diabetic keratocytes stimulated with interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha). METHODS: Normal and diabetic keratocytes were primarily cultured and treated with 20 ng/ml IL-1alpha and TNF-alpha for 6 h. cDNA was hybridized to an oligonucleotide microarray. Genes identified by the microarray were further evaluated by real-time PCR. RESULTS: Diabetic keratocytes over-expressed components of the MAPK and Notch pathways, and under-expressed components of the insulin, calcium, and TGF-beta pathways. Cytokine treated diabetic keratocytes differentially expressed components of the TGF-beta and MAPK pathways. After IL-1alpha and TNF-alpha treatment, nine genes were under-expressed, falling in the insulin, TGF-beta, and Toll-like receptor pathways. Real-time PCR showed a significant decrease in the IL-6 and TGF-beta2 genes and a significant increase in the Ppm1a gene. CONCLUSIONS: There were some differences in gene expression between normal and diabetic keratocytes related to signal transduction pathways, such as the insulin, MAPK, calcium, and TGF-beta pathways. In addition, IL-1alpha and TNF-alpha stimulating the insulin, TGF-beta, and Toll-like receptor signaling pathways may have different effects in diabetic keratocytes.