Long-term untreated streptozotocin-diabetes leads to increased expression and elevated activity of prostaglandin H2synthase in blood platelets

Hypoglycemic Effect and Experimental Validation of Scutellariae Radix based on Network Pharmacology and Molecular Docking

Scutellariae Radix (SR) is a well-known traditional herb that has good pharmacological effects against diabetes. However, the mechanism of SR against diabetes is not clear. In this study, the ingredient–target–pathway relationship and hypoglycemic effect of SR on diabetes were explored using network pharmacology, molecular docking and an animal experiment. The targets of SR and diabetes were mined. The selected targets were studied using Gene Ontology (GO) enrichment analysis and pathway enrichment analysis. The network of active components, targets and pathways was integrated to analyze the ingredient–target–pathway relationship. Then, the correspondence between the active components and targets was verified using molecular docking. Finally, an animal experiment was used to verify the hypoglycemic effect of SR. There were 52 components and 22 targets for the hypoglycemic effect of SR. We identified 18 biological processes, 9 cellular components, 15 molecular functions and 25 signaling pathways. Molecular docking results indicated that the targets of diabetes bound strongly to the main components. The animal experiments showed that SR could significantly decrease the blood glucose level of diabetic rats (p ≤ 0.05). This study explored the potential targets and signaling pathways of SR in diabetes, and the results may help to illustrate the hypoglycemic mechanism of SR.

Based on urine metabolomics to study the mechanism of Qi-deficiency affecting type 2 diabetes rats using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Qi-deficiency also called energy deficiency, which approximates to the term of sub-health in contemporary medical theory. Diabetes is similar to the symptoms of "xiaoke" in traditional Chinese medicine (TCM) which is linked with Qi-deficiency. However, the mechanism of Qi-deficiency on type 2 diabetes (T2D) has not been completely elucidated. In this study, a model on Qi-deficiency T2D rat was established by using diet with high fat and high sugar and small-dose STZ induction combined with exhaustive swimming, and the model was evaluated by pathological section, hematological index and serum biochemical parameters. Applying urine metabolomics based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry to explore the underlying molecular mechanism of Qi-deficiency on T2D and 32 urinary metabolites were identified as prospective biomarkers for Qi-deficiency T2D rats. Metabolic pathway analysis indicated that synthesis and degradation of ketone bodies, starch and sucrose metabolism, phenylalanine metabolism, arachidonic acid metabolism, butanoate metabolism and TCA cycle, etc., were closely related to potential mechanisms of Qi-deficiency on T2D. The metabolomics results can provide reliable data support for complex TCM syndrome diagnosis.

Effects of three-month streptozotocin-induced diabetes in mice on blood platelet reactivity, COX-1 expression and adhesion potential

Diabetes is associated with an increased risk of cardiovascular disease. This is partially attributed to an altered activation status of blood platelets in this disease. Previously, alterations have been shown in COX-1 and protease activated receptor (PAR)-3 receptor expression in platelets in two animal models of diabetes, there have not been studies which address expression of these proteins in mice with long-term streptozotocin (STZ)-induced diabetes. We have also addressed the effect of diabetes on platelet adhesion under flow conditions. With the use of flow cytometry, we have shown that certain markers of platelet basal activation, such as active form of α_{II b} β₃ and of CD40L were increased in STZ-induced diabetic mice. Platelets from STZ-induced diabetic mice were also more reactive when stimulated with PAR-4 activating peptide as revealed by higher expression of active form of α_{II b} β₃ , membrane-bound on vWillebrand Factor and binding of exogenous fluorescein isothyanate-labelled fibrinogen. Expression of COX-1 and production of thromboxane A₂ in platelets of STZ-induced diabetic mice were higher than in control animals. We observed no effect of diabetes on ability of platelets to form stable adhesions with fibrinogen in flow conditions. We conclude that although certain similarities exist between patterns of activation of platelets in animal models of diabetes, the differences should also be taken into account.

Effects of kisspeptin on diabetic rat platelets

Hyperglycemia, hyperlipidemia, and free radicals result in platelet activation and atherogenesis. Kisspeptin (KP) is able to regulate metabolism, hemostasis, and the development of atherosclerosis. We examined whether platelet aggregation of streptozotocin-induced diabetic rats depends on the inducer type and if KP-13 and RF-9 (a kisspeptin receptor modifier) can influence platelet function. We measured the speed and the maximum of aggregation, along with the area under the curve. Serum glucose and calcium levels and urine formation of diabetic animals increased, while the body mass and platelet count decreased. Collagen was the most effective inducer of platelet aggregation. The aggregability of nondiabetic platelets was elevated in the presence of 5 × 10−8 mol/L KP-13. This effect was less expressed in diabetic animals. The effectivity of RF-9 was stronger than that of KP-13 in nondiabetic platelets, however it was ineffective in diabetic animals. RF-9 pre-treatment did not change the effects of 5 × 10−8 mol/L KP-13 in either animal group. The in vivo activation of diabetic platelets, which may be due to elevated serum calcium, induces thrombocytopenia and may lead to reduced in vitro aggregability. We could not demonstrate the antagonistic effect of RF-9 against KP-13 in isolated platelets.

Enhanced adhesion of blood platelets to intact endothelium of mesenteric vascular bed in mice with streptozotocin-induced diabetes is mediated by an up-regulated endothelial surface deposition of VWF - In vivo study

Numerous in vitro experiments have confirmed that a dysfunctional endothelium is characterized by, inter alia, a higher affinity for binding of platelets and leukocytes. However, there is still no direct evidence for greater interaction between platelets and intact endothelium in in vivo animal models of diabetes. Therefore, the present study examines the pro-adhesive properties of endothelium change in vivo as an effect of streptozotocin (STZ)-induced diabetes and the role of two key platelet receptors: GPIb-IX-V and GPIIb/IIIa. Mice of C57BL strain with streptozotocin-induced diabetes were used in the study. Flow cytometry was used to assess basal activation and reactivity of platelets. Adhesion of platelets to the vascular wall was visualized with the use of intravital microscopy in mesentery. The contribution of GPIIb/IIIa and GPIb-IX-V was evaluated by the injection of Fab fragments of respective antibodies. The integrity of the endothelium and vWf expression were evaluated histochemically. Basal activation and reactivity of platelets in streptozotocin-diabetic mice were elevated. Blood platelets adhered more often to the vascular wall of diabetic mice than nondiabetic animals: 11.9 (6.4; 32.8) plt/min/mm² (median [IQR]) vs 2.7 (1.3; 6.4) plt/min/mm². The injection of anti-GPIbα antibodies decreased the number of adhering platelets from 89.5 (34.0; 113.1) plt/min/mm² (median [IQR]) in mice treated with isotype antibodies to 3.1 (1.7; 5.6) plt/min/mm² in mice treated with blocking antibodies. The effect of GPIIb/IIIa blockage was not significant. Immunohistochemistry revealed a higher expression of vWF in the endothelium of STZ mice, but no substantial changes in endothelial morphology were detected. To conclude, the study shows that the platelets interact more frequently with the mesenteric vascular bed in mice with 1-month STZ-induced diabetes than in healthy mice. These interactions are mediated via platelet GPIb-IX-V and are driven by increased expression of vWF in endothelial cells.