Antioxidant profile of salivary glands in high fat diet-induced insulin resistance rats.

OBJECTIVE: There is no study analyzing the salivary antioxidant profile in the course of the insulin resistance. MATERIALS AND METHODS: Rats were divided into two groups. One group was fed with a normal diet, another one with a high fat diet for 5 weeks. The analysis included: catalase (CAT), superoxide dismutase, peroxidase activities, uric acid, and total antioxidant status concentrations. RESULTS: The activity of peroxidase in both kind of glands of insulin resistance rats was significantly reduced than in the control rats. The protein concentration, total amount of total antioxidant status in the parotid glands of insulin resistance rats were significantly lower than in the control glands The total amount of superoxide dismutase, CAT, and uric acid in the parotid glands of insulin resistance rats were significantly elevated in comparison with the control rats. The median values of the total amount of superoxide dismutase, CAT, peroxidase, total antioxidant status were significantly higher in the parotid than in the submandibular glands of the insulin resistance and control rats. CONCLUSION: Parotid and submandibular glands of rats react differently when exposed to insulin resistance condition; however, the parotid glands seem to be more affected. The main source of antioxidants is parotid glands of rats.

Sphingolipid profiles are altered in prefrontal cortex of rats under acute hyperglycemia.

Diabetes type 1 is a common autoimmune disease manifesting by insulin deficiency and hyperglycemia, which can lead to dementia-like brain dysfunctions. The factors triggering the pathological processes in hyperglycemic brain remain unknown. We reported in this study that brain areas with different susceptibility to diabetes (prefrontal cortex (PFC), hippocampus, striatum and cerebellum) revealed differential alterations in ceramide (Cer) and sphingomyelin (SM) profiles in rats with streptozotocin-induced hyperglycemia. Employing gas-liquid chromatography, we found that level of total Cer increased significantly only in the PFC of diabetic animals, which also exhibited a broad spectrum of sphingolipid (SLs) changes, such as elevations of Cer-C16:0, -C18:0, -C20:0, -C22:0, -C18:1, -C24:1 and SM-C16:0 and -C18:1. In opposite, only minor changes were noted in other examined structures. In addition, de novo synthesis pathway could play a role in generation of Cer containing monounsaturated fatty acids in PFC during hyperglycemia. In turn, simultaneous accumulation of Cers and their SM counterparts may suggest that overproduced Cers are converted to SMs to avoid excessive Cer-mediated cytotoxicity. We conclude that broad changes in SLs compositions in PFC induced by hyperglycemia may provoke membrane rearrangements in some cell populations, which can disturb cellular signaling and cause tissue damage.

Metronidazole affects breast cancer cell lines.

PURPOSE: The aim of our study was to evaluate the impact of metronidazole (MTZ) on cytotoxicity and DNA synthesis in MCF-7 (estrogen receptor positive) and MDA-MB-231 (estrogen receptor negative) breast cancer cell lines. MATERIAL/METHODS: Toxicity of MTZ was determined by MTT test. MCF-7 and MDA-MB-231 cells were incubated with metronidazole used in different concentrations for 24, 48 and 72 hours. The effect of MTZ on DNA synthesis was measured as [3H]-thymidine incorporation. RESULTS: We showed that MTZ in concentration 250 µg/ml significantly increases the growth of MCF-7 cell lines after 24 hours of incubation, but it reduces cell viability in concentrations 1 and 10 µg/ml 72 hours after the drug application. Significant increase of MDA-MB-231 cell viability was obtained in MTZ concentration of 250 µg/ml after 24 and 72 hours. The increase of [3H]-thymidine incorporation in MCF-7 cell line treated with MTZ in concentration 250 µg/ml was statistically significant after 24 hours. Great suppression of cell proliferation was obtained in MDA-MB-231 breast cell line after application of the following concentrations of MTZ: 0.1 µg/ml (after 24 hours) and 0.1, 10, 50, 250 µg/ml (after 72h). CONCLUSIONS: We found that metronidazole exerts different dose- and time- dependent effects on human breast cancer cell lines characterized by presence or absence of estrogen receptors. We suggest that these discrepancies may be influenced by the estrogen signaling.