Effects of rosiglitazone with insulin combination therapy on oxidative stress and lipid profile in left ventricular muscles of diabetic rats

Protective effect of rosiglitazone on microscopic and oxidative stress parameters of ram sperm after freeze-thawing

The purpose of this study was to investigate the effects of rosiglitazone on ram semen after cryopreservation on the quality of thawed sperm. Sperm motility, membrane functionality, viability, total abnormality, acrosome membrane integrity, mitochondrial activity, reactive oxygen species production, ATP content and apoptotic features were assessed after thawing. Rosiglitazone at concentration of 60 µM resulted in the highest (P < 0.05) total motility, progressive motility and straight-line velocity. The percentages of average path velocity and curvilinear velocity were greater in the 60 µM group. Different concentrations of rosiglitazone did not have significant effects on amplitude of the lateral head displacement, linearity and straightness. The highest amounts of membrane functionality and mitochondrial activity after freeze-thawing were observed in groups containing 60 µM. By increasing the rosiglitazone level to 80 µM, no positive effect was observed in most of the evaluated parameters. The lowest ROS concentration was recorded in 60 µM rosiglitazone group (P < 0.05). The group containing 60 µM rosiglitazone also produced the lowest significant percentage of apoptosis-like changes and dead sperm. A greater (P < 0.05) percentage of acrosome integrity in frozen-thawed spermatozoa was observed in the 60 µM rosiglitazone group. There was no significant difference between 40 and 60 µM rosiglitazone in intact acrosome of ram thawed semen. The result showed that supplementation in ram semen extender with rosiglitazone had a positive role in the regulation of ram sperm motility and had strong protective effect on the sperm membrane and acrosome integrity.

Effects of first-line diabetes therapy with biguanides, sulphonylurea and thiazolidinediones on the differentiation, proliferation and apoptosis of islet cell populations

AIMS

Metformin, rosiglitazone and sulfonylureas enhance either insulin action or secretion and thus have been used extensively as early stage anti-diabetic medication, independently of the aetiology of the disease. When administered to newly diagnosed diabetes patients, these drugs produce variable results. Here, we examined the effects of the three early stage oral hypoglycaemic agents in mice with diabetes induced by multiple low doses of streptozotocin, focusing specifically on the developmental biology of pancreatic islets.

METHODS

Streptozotocin-treated diabetic mice expressing a fluorescent reporter specifically in pancreatic islet α-cells were administered the biguanide metformin (100 mg/kg), thiazolidinedione rosiglitazone (10 mg/kg), or sulfonylurea tolbutamide (20 mg/kg) for 10 days. We assessed the impact of the treatment on metabolic status of the animals as well as on the morphology, proliferative potential and transdifferentiation of pancreatic islet cells, using immunofluorescence.

RESULTS

The effect of the therapy on the islet cells varied depending on the drug and included enhanced pancreatic islet β-cell proliferation, in case of metformin and rosiglitazone; de-differentiation of α-cells and β-cell apoptosis with tolbutamide; increased relative number of β-cells and bi-hormonal insulin + glucagon + cells with metformin. These effects were accompanied by normalisation of food and fluid intake with only minor effects on glycaemia at the low doses of the agents employed.

CONCLUSIONS

Our data suggest that metformin and rosiglitazone attenuate the depletion of the β-cell pool in the streptozotocin-induced diabetes, whereas tolbutamide exacerbates the β-cell apoptosis, but is likely to protect β-cells from chronic hyperglycaemia by directly elevating insulin secretion.

Effect of rosiglitazone on inflammatory cytokines and oxidative stress after intensive insulin therapy in patients with newly diagnosed type 2 diabetes

OBJECTIVE

To evaluate the effect of insulin sensitizer on inflammatory cytokines and oxidative stress in patients with newly diagnosed type 2 diabetes mellitus (T2DM).

METHODS

After intensive insulin therapy, patients with newly diagnosed T2DM were continuously treated with either insulin sensitizer or insulin for 48 weeks, and then their inflammatory cytokine and oxidative stress levels were measured.

RESULTS

Tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, hypersensitive C reactive protein (hs-CRP), malondialdehyde (MDA), and 8-iso-prostaglandin F2α (8-iso-PGF_2α) levels of the rosiglitazone (RSG) group and the rosiglitazone combined with metformin (RSG + metformin) group were significantly reduced after the treatments (P < 0.05). Hs-CRP, MDA, and 8-iso-PGF_2α levels of the metformin group were significantly reduced after the treatments (P < 0.05). Superoxide dismutase (SOD) and total antioxidant capacity (TAC) were significantly increased after the treatments in all three groups (P < 0.05 and P < 0.01).

CONCLUSION

Early application of insulin sensitizers improved inflammation and oxidative stress in patients with newly diagnosed T2DM.

Effects of HCG on human epithelial ovarian cancer vasculogenic mimicry formation in vivo

Ovarian cancer is the leading cause of mortality due to gynecological malignancy, and vasculogenic mimicry (VM) formation is correlated with poor prognosis. In a previous study, the present authors observed that human chorionic gonadotropin (HCG) could promote VM formation in three-dimensional OVCAR-3 cell cultures. In order to investigate whether HCG could promote VM formation in ovarian cancer in vivo, the role of OVCAR-3 cells overexpressing or depleted of chorionic gonadotropin, beta polypeptide 5 (CGB5, which is the fifth subunit of β-HCG and was identified as the key part of HCG) were injected into nude mice in the present study, while BeWo cells were used as a positive control. The results demonstrated that overexpressed CGB5 promoted xenografts tumor formation in nude mice, and the results of hematoxylin and eosin and cluster of differentiation (CD)34-periodic acid-Schiff dual staining revealed that CGB5 promoted VM formation. Furthermore, reverse transcription-polymerase chain reaction and immunochemistry staining demonstrated that the expression of the vascular markers CD31, vascular endothelial growth factor and factor VIII was also upregulated in the CGB5-overexpressing xenografts tumors. In addition, the expression of luteinizing hormone receptor (LHR), the receptor of CGB5, was increased in CGB5-overexpressing cells. In conclusion, CGB5 may promote tumor growth and VM formation via activation of the LHR signal transduction pathway, which may support a novel strategy for ovarian cancer therapy.

The effects of crocin, insulin and their co-administration on the heart function and pathology in streptozotocin-induced diabetic rats

OBJECTIVE

Crocin is a saffron constituent with a potent anti-oxidant activity. The present study investigated the effects of crocin and insulin treatments (alone or in combination) on cardiac function and pathology in diabetic rats.

MATERIALS AND METHODS

Diabetes was induced by intraperitoneal (i.p.) injection of streptozotocin (STZ, 50 mg/kg). Thereafter, crocin (5, 10 and 20 mg/kg, i.p.), subcutaneous (s.c.) injection of insulin (4 IU/kg) and their combination were administered for eight weeks. Blood glucose level and whole heart and body weights were measured. Electrocardiography (ECG) was carried out using the lead II. Serum concentrations of lactate dehydrogenase (LDH), creatine kinase-MB isoenzyme (CK-MB), and the heart tissue malodialdehyde (MDA) and superoxide dismutase (SOD) contents were determined. The heart lesions were evaluated by light microscopy.

RESULTS

STZ decreased body weight and increased whole heart weight/body weight ratio. It also decreased heart rate, and increased RR and QT intervals and T wave amplitude. STZ increased blood glucose, serum LDH and CK-MB levels, augmented heart tissue MDA content, decreased SOD content of heart tissue, and produced hemorrhages, degeneration, interstitial edema, and fibroblastic proliferation in the heart tissue. Crocin (10 and 20 mg/kg, i.p.), insulin (4 IU/kg, s.c.) and their combination (5 mg/kg of crocin with 4 IU/kg of insulin) treatments recovered the ECG, biochemical and histopathological changes induced by STZ.

CONCLUSION

The results showed cardioprotective effects of crocin and insulin in STZ-induced diabetic rats. The antioxidant and anti-hyperglycemic properties of crocin and insulin may be involved in their cardioprotective actions.