OBJECTIVES: To investigate the effects of quercetin on cuproptosis and L-type calcium currents in the myocardium of diabetic rats. METHODS: Forty SD rats were randomized into control group and diabetic model groups. The rat models of diabetes mellitus (DM) induced by high-fat and high-sugar diet combined with streptozotocin (STZ) injection were further divided into DM model group, quercetin treatment group, and empagliflozin treatment group (n=10). Blood glucose and body weight were measured every other week, and cardiac function of the rats was evaluated using echocardiography. HE staining, Sirius red staining, and wheat germ agglutinin (WGA) analysis were used to observe the changes in myocardial histomorphology, and serum copper levels and myocardial FDX1 expression were detected. In cultured rat cardiomyocyte H9c2 cells with high-glucose exposure, the effects of quercetin and elesclomol, alone or in combination, on intracellular CK-MB and LDH levels and FDX1 expression were assessed, and the changes in L-type calcium currents were analyzed using patch-clamp technique. RESULTS: The diabetic rats exhibited elevated blood glucose, reduced body weight, impaired left ventricular function, increased serum copper levels and myocardial FDX1 expression, decreased L-type calcium currents, and prolonged action potential duration. Quercetin and empagliflozin treatment significantly lowered blood glucose, improved body weight, and restored cardiac function of the diabetic rats, and compared with empagliflozin, quercetin more effectively reduced serum copper levels, downregulated FDX1 expression, and enhanced myocardial L-type calcium currents in diabetic rats. In H9c2 cells, high glucose exposure significantly increased myocardial expressions of FDX1, CK-MB and LDH, which were effectively lowered by quercetin treatment; Elesclomol further elevated FDX1, CK-MB and LDH levels in the exposed cells, and these changes were not significantly affected by the application of quercetin. CONCLUSIONS Quercetin ameliorates myocardial injury in diabetic rats possibly by suppressing myocardial cuproptosis signaling and restoring L-type calcium channel activity.
Animals ; Quercetin/pharmacology* ; Calcium Channels, L-Type/metabolism* ; Diabetes Mellitus, Experimental/metabolism* ; Rats, Sprague-Dawley ; Rats ; Myocytes, Cardiac/drug effects* ; Myocardium/pathology* ; Male

OBJECTIVE: To investigate the effects of Bax inhibitor 1 (BI- 1) and optic atrophy protein 1 (OPA1) on vascular calcification (VC). METHODS: Mouse models of VC were established in ApoE-deficient (ApoE^-/-) diabetic mice by high-fat diet feeding for 12 weeks followed by intraperitoneal injections with N^ε-carboxymethyl-lysine for 16 weeks. ApoE^-/- mice (control group), ApoE^-/- diabetic mice (VC group), ApoE^-/- diabetic mice with BI-1 overexpression (VC + BI-1^TG group), and ApoE^-/- diabetic mice with BI-1 overexpression and OPA1 knockout (VC+BI-1^TG+OPA1^-/- group) were obtained for examination of the degree of aortic calcification using von Kossa staining. The changes in calcium content in the aorta were analyzed using ELISA. The expressions of Runt-related transcription factor 2 (RUNX2) and bone morphogenetic protein 2 (BMP-2) were detected using immunohistochemistry, and the expression of cleaved caspase-3 was determined using Western blotting. Cultured mouse aortic smooth muscle cells were treated with 10 mmol/L β-glycerophosphate for 14 days to induce calcification, and the changes in BI-1 and OPA1 protein expressions were examined using Western blotting and cell apoptosis was detected using TUNEL staining. RESULTS: ApoE^-/- mice with VC showed significantly decreased expressions of BI-1 and OPA1 proteins in the aorta (P=0.0044) with obviously increased calcium deposition and expressions of RUNX2, BMP-2 and cleaved caspase-3 (P= 0.0041). Overexpression of BI-1 significantly promoted OPA1 protein expression and reduced calcium deposition and expressions of RUNX2, BMP-2 and cleaved caspase-3 (P=0.0006). OPA1 knockdown significantly increased calcium deposition and expressions of RUNX2, BMP-2 and cleaved caspase-3 in the aorta (P=0.0007). CONCLUSION BI-1 inhibits VC possibly by promoting the expression of OPA1, reducing calcium deposition and inhibiting osteogenic differentiation and apoptosis of the vascular smooth muscle cells.
Animals ; Apolipoproteins E/metabolism* ; Calcium/metabolism* ; Caspase 3/metabolism* ; Cells, Cultured ; Core Binding Factor Alpha 1 Subunit/metabolism* ; Diabetes Mellitus, Experimental/pathology* ; GTP Phosphohydrolases/metabolism* ; Membrane Proteins/metabolism* ; Mice ; Mice, Knockout ; Muscle, Smooth, Vascular/pathology* ; Myocytes, Smooth Muscle/pathology* ; Optic Atrophy, Autosomal Dominant/pathology* ; Osteogenesis ; Vascular Calcification/pathology* ; bcl-2-Associated X Protein/metabolism*

OBJECTIVE: To analyze the changes of blood biochemical index and the pathological changes of myocardium and kidney in type 2 diabetic mouse at different time points, which can provide the basis for the selection of type 2 diabetic modeling time for later research. METHODS: After 6 weeks of feeding with high-fat diet, 24 healthy male ICR mice were injected with streptozocin (STZ, 30 mg/kg) intraperitoneally for 5 days to establish diabetic models. After 9 days, a random blood glucose ≥ 11.1 mmol / L was measured as diabetic mice. 4, 6 and 8 weeks after successfully preparing the diabetic mouse, 8 diabetic mice (a group)would be sacrificed each time. Then the biochemical and pathological conditions were analyzed: ① the indexes of heart and kidney were calculated. ②the serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), creatinine (Cr) and blood urine nitrogen (BUN) were determined. ③ Histopathological changes of myocardium and renal tissues were observed by hematoxylin and eosin (HE) staining. Masson staining was used to observe the fibrosis of myocardium. PAS staining was adopted to observe the pathological changes of renal tissue. In addition, 8 ICR male mice were taken as the control group. RESULTS: At the 4, 6 and 8 week, cardiac organ coefficient, the values of LDH and CK were all increased compared with the control group. Cardiomyocyte hypertrophy and myocardial fibrosis could be observed. Renal organ coefficient, the values of Cr and BUN were increased. Glomerular hypertrophy, basement membrane thickening and atrophy could be perceived. CONCLUSION At the 6 week, related biochemical and pathological changes in diabetic mice were comparatively obvious and breeding time was relatively short. Thus, 6 weeks after the preparation of the diabetic mice would be the optimal time for type 2 diabetes mellitus modeling, proper for inventions of drugs and other research purposes including pathology, physiology, biochemistry, etc.
Animals ; Diabetes Mellitus, Experimental ; pathology ; Diabetes Mellitus, Type 2 ; pathology ; Disease Models, Animal ; Kidney ; pathology ; Male ; Mice ; Mice, Inbred ICR ; Streptozocin

OBJECTIVE: To investigate the intervention of curcumin and its analogue J7 on oxidative stress injury in testis of type 2 diabetic rats. METHODS: Sixty male SD rats, 10 rats were chosen as normal control group (NC), the other 50 rats were assigned to experiment group. Experiment diabetic rats were induced by high-fat food and intraperitoneal injection of steptozotocin (STZ). After the model was established successfully, diabetic rats were divided into four groups randomly: diabetes mellitus group (DM, n=12), curcumin treatment group (CUR, n=10), high dose treatment group of J7 (J+, n=10), low dose treatment group of J7 (J-, n=10). The CUR group were intragastrically administered with curcumin 20 mg/kg daily, in addition, the J+ group and the J- group were intragastrically administered with J7 20 mg/kg and 10 mg/kg daily respectively. After 8 weeks, the fast blood glucose was detected biochemically. The activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) were detected by hydroxylamine method and thiobarbituric acid method respectively. The protein expressions of the nuclear factor-erythroid 2-related factor 2 (tNrf2), phosphorylation of Nrf2 (pNrf2), catalase (CAT), NAD(P)H quinine oxidoreductase 1 (NQO1) were measured by Western blot. The mRNA expressions of CAT, NQO1, hemeoxygenase-1 (HO1) were measured by quantitative real-time PCR (qRT-PCR). Morphological structure of testis was observed by hematoxylin-eosin (HE) staining. The expressions of Nrf2 and CAT were also detected by immunohistochemical method. RESULTS: The levels of fast blood glucose and MDA in DM group were increased significantly(P＜0.05), while the body weight, the activity of SOD, the protein expressions of pNrf2/tNrf2, CAT, NQO1 and the mRNA expressions of CAT, NQO1, HO1 were decreased (P＜0.05). Under light microscope, the DM group showed disrupted histological appearance. Immunohistochemistry showed that the protein expressions of Nrf2 around the nucleus and CAT were decreased. With the treatment of curcumin and J7, the MDA levels in the three treatment groups were decreased (P＜0.05). The activity of SOD, the protein expressions of pNrf2/tNrf2, CAT, NQO1 and the mRNA expressions of NQO1, HO1 were increased (P＜0.05). the levels of fast blood glucose were decreased in the J+ and J- group (P＜0.05), and the mRNA expression of CAT was increased in the J+ group (P＜0.05). The ratio of pNrf2/tNrf2 in the J+ group was significantly higher than that in CUR and J- group (P＜0.05). The protein level of CAT in the J+ group was also significantly higher than that in J- group (P＜0.05). There were no significant differences in other indexes among the three treatment groups. Under light microscope, the morphology was obviously improved in the three treatment groups. Immunohistochemistry showed that the protein expressions of Nrf2 around the nucleus and CAT were increased in the three treatment groups. It was suggested that high dose J7 had better antioxidant stress ability in testis of diabetic rats. CONCLUSION Curcumin and J7 could inhibit the oxidative stress damage of testicular tissue in diabetic rats, which might be related with the activation of the Nrf2-ARE signaling pathway.
Animals ; Blood Glucose ; analysis ; Curcumin ; analogs & derivatives ; pharmacology ; Diabetes Mellitus, Experimental ; Diabetes Mellitus, Type 2 ; Male ; Malondialdehyde ; metabolism ; NF-E2-Related Factor 2 ; metabolism ; Oxidative Stress ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Superoxide Dismutase ; metabolism ; Testis ; drug effects ; pathology

Objective To investigate the sequential changes of the number of neutrophils and myofibroblasts during diabetic wound healing, and discuss its application value in wound age estimation. Methods Diabetic DB mice and mice of the same age in the normal control group were selected, a wound healing model was established, wound samples were taken at different time points, while the number of neutrophils and myofibroblasts during diabetic wound healing were determined by immunohistochemical staining technique. Results The number of infiltrated neutrophils in the wounds of control and diabetic groups reached the peak respectively at 12 h and 5 d after injury. Compared with the control group, the number of neutrophils in the diabetic group decreased significantly from 6 h to 1 d after injury, but increased markedly from 5 d to 14 d. From 5 d to 10 d after injury, the average number of neutrophils at high magnification in wounds of the diabetic group was over 30, while that of neutrophils in wounds of the control group was less than 20. Myofibroblasts appeared in wounds from 3 d to 14 d after injury in the control group and from 5 d to 14 d after injury in the diabetic group. The difference in the number of myofibroblasts in wounds between control group and diabetic group from 3 to 7 d after injury had statistical significance. Conclusion In comparison with normal wound healing, the number of neutrophils and myofibroblasts during diabetic wound healing shows different sequential changes. The results of this study can provide reference for wound age estimation of patients with severe diabetes.
Animals ; Diabetes Mellitus, Experimental/pathology* ; Mice ; Myofibroblasts ; Neutrophils ; Wound Healing/physiology*

The present study aimed to evaluate the anti-diabetic property of peanut shell polyphenol extracts (PSPEs). Diabetic rats were oral-administrated with PSPE at doses of 50, 100, and 200 mg/kg body weight (BW) per day for 28 consecutive days, with metformin (Met) as a positive control. The results showed that, similar to the Met treatment, administration of PSPE caused significant decreases in food intake, water intake, fasting blood glucose, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and methane dicarboxylic aldehyde in serum, and significant increases in BW, insulin level, high-density lipoprotein cholesterol, superoxide dismutase, glutathione, and liver glycogen. Further, glucose tolerance was markedly improved in the PSPE-treated diabetic groups. Histopathological results showed that PSPE improved cellular structural and pathological changes in liver, kidney, and pancreatic islets. Collectively, the results indicated that the hypoglycemic effects of PSPE on high-fat diet/streptozotocin (HFD/STZ)-induced diabetes are comparable to Met, though their exact mechanism actions are still under investigation. Therefore, the current study suggests that PSPE could be a potential health-care food supplement in the management of diabetes.
Animals ; Arachis/chemistry* ; Diabetes Mellitus, Experimental/pathology* ; Hypoglycemic Agents/pharmacology* ; Lipids/blood* ; Liver/pathology* ; Male ; Oxidative Stress/drug effects* ; Plant Extracts/pharmacology* ; Polyphenols/pharmacology* ; Rats ; Rats, Wistar ; Streptozocin

OBJECTIVE: The present study aims at determining the stability of a popular type 2 diabetes rat model induced by a high-fat diet combined with a low-dose streptozotocin injection. METHODS: Wistar rats were fed with a high-fat diet for 8 weeks followed by a one-time injection of 25 or 35 mg/kg streptozotocin to induce type 2 diabetes. Then the diabetic rats were fed with regular diet/high-fat diet for 4 weeks. Changes in biochemical parameters were monitored during the 4 weeks. RESULTS: All the rats developed more severe dyslipidemia and hepatic dysfunction after streptozotocin injection. The features of 35 mg/kg streptozotocin rats more resembled type 1 diabetes with decreased body weight and blood insulin. Rats with 25 mg/kg streptozotocin followed by normal diet feeding showed normalized blood glucose level and pancreatic structure, indicating that normal diet might help recovery from certain symptoms of type 2 diabetes. In comparison, diabetic rats fed with high-fat diet presented decreased but relatively stable blood glucose level, and this was significantly higher than that of the control group (P<0.05). CONCLUSIONS This model easily recovers with normal diet feeding. A high-fat diet is suggested as the background diet in future pharmacological studies using this model.
Animals ; Blood Glucose ; metabolism ; Diabetes Mellitus, Experimental ; blood ; etiology ; physiopathology ; Diabetes Mellitus, Type 2 ; blood ; etiology ; physiopathology ; Diet, High-Fat ; adverse effects ; Insulin ; blood ; Lipids ; blood ; Liver ; drug effects ; pathology ; physiopathology ; Male ; Malondialdehyde ; blood ; Oxidative Stress ; Rats ; Rats, Wistar ; Streptozocin ; administration & dosage ; toxicity ; Superoxide Dismutase ; blood ; Uric Acid ; blood

Previous studies have shown that oxidative stress and corporal fibrosis in penile tissues of rats were key pathological factors of erectile dysfunction induced by diabetic mellitus (DMED). Lipoxin A4 (LXA4) was reported to inhibit oxidative stress and fibrosis diseases, while whether it could exert a protective role on erectile function was not clear. Type I diabetic mellitus (DM) was induced in thirty male 10-week-old Sprague-Dawley rats using streptozotocin. Ten weeks later, twenty-two rats with DMED confirmed by an apomorphine test were divided into two groups: the DMED group (n = 11) and the DMED + LXA4 group (n = 11; LXA4 injection daily for 4 weeks). In addition, another ten age-matched rats formed the Control group. We found that erectile function was significantly impaired in the DMED group compared with the Control group, but was improved in the DMED + LXA4 group. Similarly, the over-activated oxidative stress and impaired endothelial function in the DMED group were both improved in the DMED + LXA4 group. Moreover, the DMED group showed serious corporal fibrosis, which was also inhibited by the treatment of LXA4 in the DMED + LXA4 group. Taken together, LXA4 could exert an inhibition role on oxidative stress and fibrosis to improve DMED effectively.
Actins/metabolism* ; Animals ; Anti-Inflammatory Agents, Non-Steroidal/pharmacology* ; Diabetes Mellitus, Experimental/physiopathology* ; Diabetes Mellitus, Type 1/physiopathology* ; Erectile Dysfunction/physiopathology* ; Fibrosis ; Lipoxins/pharmacology* ; Male ; Nitric Oxide/metabolism* ; Nitric Oxide Synthase Type III/metabolism* ; Oxidative Stress/drug effects* ; Penile Erection/drug effects* ; Penis/pathology* ; Rats ; Rats, Sprague-Dawley

In this study, we investigated the effects of chronic aluminum (Al) exposure for 10 weeks on cell proliferation and neuroblast differentiation in the hippocampus of type 2 diabetic rats. Six-week-old Zucker diabetic fatty (ZDF) and Zucker lean control (ZLC) rats were selected and randomly divided into Al- and non-Al-groups. Al was administered via drinking water for 10 weeks, after which the animals were sacrificed at 16 weeks of age. ZDF rats in both Al- and non-Al-groups showed increases in body weight and blood glucose levels compared to ZLC rats. Al exposure did not significantly affect body weight, blood glucose levels or pancreatic β-cells and morphology of the pancreas in either ZLC or ZDF rats. However, exposure to Al reduced cell proliferation and neuroblast differentiation in both ZLC and ZDF rats. Exposure to Al resulted in poor development of the dendritic processes of neuroblasts in both ZLC and ZDF rats. Furthermore, onset and continuation of diabetes reduced cell proliferation and neuroblast differentiation, and Al exposure amplified reduction of these parameters. These results suggest that Al exposure via drinking water aggravates the impairment in hippocampal neurogenesis that is typically observed in type 2 diabetic animals.
Aluminum/*toxicity ; Animals ; Blood Glucose/analysis ; Cell Differentiation/drug effects ; Cell Proliferation/drug effects ; Diabetes Mellitus, Experimental/pathology ; Diabetes Mellitus, Type 2/*pathology ; Disease Models, Animal ; Hippocampus/*drug effects ; Neurogenesis/*drug effects ; Random Allocation ; Rats, Zucker

OBJECTIVETo explore the effects of ghrelin on learning and memory abilities and expressions of DKK-1 and β-catenin in the hippocampus of diabetic rats.

METHODSSixty male SD rats were randomly assigned into 4 groups, namely the control group, diabetic group, ghrelin-treated diabetic group (DM1 group), and ghrelin- and D-lys3-GHRP-6 (a GHSR-1a receptor antagonist)-treated diabetic group (DM2 group). Diabetic rat models were established by a single intraperitoneal injection of streptozotocin (65 mg/kg). The learning and memory abilities of the rats were assessed with Morris water maze (MWM) test. The ultrastructure of the hippocampal CA1 area of the rats were observed with electron microscopy. Serum levels of DKK-1 were examined by ELISA, and the expressions of DKK-1 and β-catenin in the hippocampus were examined by quantitative real-time PCR and Western blotting.

RESULTSCompared with the control group, the diabetic rats exhibited significantly impaired learning and memory abilities (P<0.05), increased expression of DKK-1 and lowered β-catenin expression in the hippocampus (P<0.05), significant ultrastructural injuries and disordered arrangement of neurons with the nuclear pycnosis in the hippocampal CA1 area. Ghrelin treatment of the diabetic rats obviously improved their learning and memory abilities (P<0.05), reduced DKK-1 and increased β-catenin expressions (P<0.05), ameliorated ultrastructural damages in the hippocampal CA1 area and restored normal neuronal alignment with clear cell layers. Such effects of ghrelin were antagonized by treatment with D-lys3-GHRP-6 in the diabetic rats.

CONCLUSIONGhrelin can alleviate learning and memory dysfunction in diabetic rats possibly by down-regulating the expressions of DKK-1 and activating the WNT signaling pathways.

Animals ; CA1 Region, Hippocampal ; cytology ; metabolism ; pathology ; Cognition ; Diabetes Mellitus, Experimental ; metabolism ; Ghrelin ; pharmacology ; Intercellular Signaling Peptides and Proteins ; metabolism ; Learning ; Male ; Memory ; Neurons ; pathology ; Oligopeptides ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Streptozocin ; beta Catenin ; metabolism