Increasing Atherosclerosis in Streptozotocin-Induced Diabetes into Four Groups of Mice

AIM: To study the protective effect of medicines on the formation of atherosclerosis in mice, it is needed to conduct the study in mice which is not genetically diabetic mice induced by streptozotocin (STZ) to produce hyperglycemia and atherosclerosis, compared with mice treated by yolk or its combination.MATERIAL AND METHODS: Fifty-six mice, Double Deutch Webster strain, male, receive 10 weeks, 20 - 30 gr bodyweight were divided into 4 groups (n = 14) i.e. control (do not received any agents), STZ (45 mg/kg/BW was injected intraperitoneally for 5 days), yolk (0.2 cc orally daily for 6 weeks), and combination of STZ and yolk (STZ: 45 mg/kg/BW intraperitoneally add 0.2 cc yolk orally). All animals were executed in the 42nd day. Then, the aorta of the mice’s heart tissue was histopathology examined. Blood glucose and cholesterol levels were determined every week.RESULTS: Hyperglycemia occurred in mice induced by STZ injection with the highest BGL (521.8 ± 48.2 mg/dl; 188.4%) in the 4th-week observation; after that BGL decrease. We found that, except the control, all treatment groups with STZ, egg yolk, and combination underwent atherosclerosis.CONCLUSION: The present study was able to demonstrate the occurrence of atherosclerosis in mice treated by STZ accompanied with increasing blood glucose and cholesterol level.

Mitochondria-Targeted Antioxidant SkQ1 Improves Dermal Wound Healing in Genetically Diabetic Mice

Oxidative stress is widely recognized as an important factor in the delayed wound healing in diabetes. However, the role of mitochondrial reactive oxygen species in this process is unknown. It was assumed that mitochondrial reactive oxygen species are involved in many wound-healing processes in both diabetic humans and animals. We have applied the mitochondria-targeted antioxidant 10-(6′-plastoquinonyl)decyltriphenylphosphonium (SkQ1) to explore the role of mitochondrial reactive oxygen species in the wound healing of genetically diabetic mice. Healing of full-thickness excisional dermal wounds in diabetic C57BL/KsJ-db−/db− mice was significantly enhanced after long-term (12 weeks) administration of SkQ1. SkQ1 accelerated wound closure and stimulated epithelization, granulation tissue formation, and vascularization. On the 7th day after wounding, SkQ1 treatment increased the number of α-smooth muscle actin-positive cells (myofibroblasts), reduced the number of neutrophils, and increased macrophage infiltration. SkQ1 lowered lipid peroxidation level but did not change the level of the circulatory IL-6 and TNF. SkQ1 pretreatment also stimulated cell migration in a scratch-wound assay in vitro under hyperglycemic condition. Thus, a mitochondria-targeted antioxidant normalized both inflammatory and regenerative phases of wound healing in diabetic mice. Our results pointed to nearly all the major steps of wound healing as the target of excessive mitochondrial reactive oxygen species production in type II diabetes.

Relaxin improves multiple markers of wound healing and ameliorates the disturbed healing pattern of genetically diabetic mice

Diabetic mice are characterized by a disrupted expression pattern of VEGF (vascular endothelial growth factor), and impaired vasculogenesis during healing. Experimental evidence suggests that RLX (relaxin) can improve several parameters associated with wound healing. Therefore we investigated the effects of porcine-derived RLX in diabetes-related wound-healing defects in genetically diabetic mice. An incisional wound model was produced on the back of female diabetic C57BL/KsJ-m+/+Leptdb (db+/db+) mice and their normal littermates (db+/+m). Animals were treated daily with porcine RLX (25 μg/mouse per day, subcutaneously) or its vehicle. Mice were killed on 3, 6 and 12 days after skin injury for measurements of VEGF mRNA and protein synthesis, SDF-1α (stromal cell-derived factor-1α) mRNA and eNOS (endothelial NO synthase) expression. Furthermore, we evaluated wound-breaking strength, histological changes, angiogenesis and vasculogenesis at day 12. Diabetic animals showed a reduced expression of VEGF, eNOS and SDF-1α compared with non-diabetic animals. At day 6, RLX administration resulted in an increase in VEGF mRNA expression and protein wound content, in eNOS expression and in SDF-1α mRNA. Furthermore, the histological evaluation indicated that RLX improved the impaired wound healing, enhanced the staining of MMP-11 (matrix metalloproteinase-11) and increased wound-breaking strength at day 12 in diabetic mice. Immunohistochemistry showed that RLX in diabetic animals augmented new vessel formation by stimulating both angiogenesis and vasculogenesis. RLX significantly reduced the time to complete skin normalization and this effect was abrogated by a concomitant treatment with antibodies against VEGF and CXCR4 (CXC chemokine receptor 4), the SDF-1α receptor. These data strongly suggest that RLX may have a potential application in diabetes-related wound disorders.

Anti-Diabetic Activity of a Mineraloid Isolate, in vitro and in Genetically Diabetic Mice

Type II diabetes is a metabolic disease mediated through multiple molecular pathways. Here, we report anti-diabetic effect of a standardized isolate from a fossil material - a mineraloid leonardite - in in vitro tests and in genetically diabetic mice. The mineraloid isolate stimulated mitochondrial metabolism in human fibroblasts and this stimulation correlated with enhanced expression of genes coding for mitochondrial proteins such as ATP synthases and ribosomal protein precursors, as measured by DNA microarrays. In the diabetic animal model, consumption of the Totala isolate resulted in decreased weight gain, blood glucose, and glycated hemoglobin. To our best knowledge, this is the first description ever of a fossil material having anti-diabetic activity in pre-clinical models.