MATERIALS AND METHODS: Six control and five DM Wistar rats were evaluated. DM was induced at 11 weeks of age using streptozotocin (STZ; 60 mg/kg, intraperitoneal). Animals were monitored up to 38 weeks of age, when plasma glucose, lipid profile, and markers specific for systemic inflammation, endothelial dysfunction, and oxidative stress were measured. The amount of fat within the aortic wall was assessed semiquantitatively using Oil Red O staining.
RESULTS: Diabetic rats presented significantly higher plasma glucose (p < 0.001), total cholesterol and triglycerides (both p = 0.02), high-sensitivity C-reactive protein (p = 0.01), and vascular endothelial growth factor (p = 0.04) levels, and significantly lower interleukin-10 (p = 0.04), superoxide dismutase (p < 0.01), and glutathione peroxidase (p = 0.01) levels than the control rats. Mild (grade 1) atherosclerotic lesions were observed in the aortic wall of 80% of the diabetic rats and in none of the control rats.
CONCLUSIONS: This study presents a STZ-induced type 1 DM rat model with one of the longest follow-ups in the literature. In this model, long-term DM created a highly pro-atherogenic environment characterised by hyperglycemia, dyslipidemia, systemic inflammation, endothelial dysfunction, and oxidative stress that resulted in the development of early aortic atherosclerotic lesions.
METHODS: Imiquimod-loaded fish oil bigel colloidal system was prepared using a blend of carbopol hydrogel and fish oil oleogel. Bigels were first characterized for their mechanical properties and compared to conventional gel systems. Ex vivo permeation studies were performed on murine skin to analyze the ability of the bigels to transport drug across skin and to predict the release mechanism via mathematical modelling. Furthermore, to analyze pharmacological effectiveness in skin cancer and controlling imiquimod-induced inflammatory side effects, imiquimod-fish oil combination was tested in vitro on epidermoid carcinoma cells and in vivo in Swiss albino mice cancer model.
RESULTS: Imiquimod-loaded fish oil bigels exhibited higher drug availability inside the skin as compared to individual imiquimod hydrogel and oleogel controls through quasi-Fickian diffusion mechanism. Imiquimod-fish oil combination in bigel enhanced the antitumor effects and significantly reduced serum pro-inflammatory cytokine levels such as tumor necrosis factor-alpha and interleukin-6, and reducing tumor progression via inhibition of vascular endothelial growth factor. Imiquimod-fish oil combination also resulted in increased expression of interleukin-10, an anti-inflammatory cytokine, which could also aid anti-tumor activity against skin cancer.
CONCLUSION: Imiquimod administration through a bigel vehicle along with fish oil could be beneficial for controlling imiquimod-induced inflammatory side effects and in the treatment of skin cancer.