Preadministration of high-dose alpha-tocopherol improved memory impairment and mitochondrial dysfunction induced by proteasome inhibition in rat hippocampus.

Objective: The ubiquitin-proteasome system plays a key role in memory consolidation. Proteasome inhibition and free radical-induced neural damage were implicated in neurodegenerative states. In this study, it was tested whether alpha-tocopherol (αT) in low and high doses could improve the long-term memory impairment induced by proteasome inhibition and protects against hippocampal oxidative stress. Methods: Alpha-tocopherol (αT) (60, 200 mg/kg, i.p. for 5 days) was administered to rats with memory deficit and hippocampal oxidative stress induced by bilateral intra-hippocampal injection of lactacystin (32 ng/µl) and mitochondrial evaluations were performed for improvement assessments. Results: The results showed that lactacystin significantly reduced the passive avoidance memory performance and increased the level of malondialdehyde (MDA), reactive oxygen species (ROS) and diminished the mitochondrial membrane potential (MMP) in the rat hippocampus. Furthermore, Intraperitoneal administration of αT significantly increased the passive avoidance memory, glutathione content and reduced ROS, MDA levels and impaired MMP. Conclusions: The results suggested that αT has neuroprotective effects against lactacystin-induced oxidative stress and memory impairment via the enhancement of hippocampal antioxidant capacity and concomitant mitochondrial sustainability. This finding shows a way to prevent and also to treat neurodegenerative diseases associated with mitochondrial impairment.

Mitochondria-Targeted Polyamidoamine Dendrimer-Curcumin Construct for Hepatocellular Cancer Treatment.

Mitochondrial malfunction plays a crucial role in cancer development and progression. Cancer cells show a substantially higher mitochondrial activity and greater mitochondrial transmembrane potential than normal cells. This concept can be exploited for targeting cytotoxic drugs to the mitochondria of cancer cells using mitochondrial-targeting compounds. In this study, a polyamidoamine dendrimer-based mitochondrial delivery system was prepared for curcumin using triphenylphosphonium ligands to improve the anticancer efficacy of the drug in vitro and in vivo. For the in vitro evaluations, various methods, such as viability assay, confocal microscopy, flow cytometry, reactive oxygen species (ROS), and real-time polymerase chain reaction analyses, were applied. Our findings showed that the targeted-dendrimeric curcumin (TDC) could successfully deliver and colocalize the drug to the mitochondria of the cancer cells, and selectively induce a potent apoptosis and cell cycle arrest at G2/M. Moreover, at a low curcumin dose of less than 25 µM, TDC significantly reduced adenosine triphosphate and glutathione, and increased the ROS level of the isolated rat hepatocyte mitochondria. The in vivo studies on the Hepa1-6 tumor-bearing mice also indicated a significant tumor suppression effect and the highest median survival days (Kaplan-Meier survival estimation and log-rank test) after treatment with the TDC construct compared to the free curcumin and untargeted construct. Besides its targeted nature and safety, the expected improved solubility and stability represent the prepared targeted-dendrimeric construct as an up-and-coming candidate for cancer treatment. The results of this study emphasize the promising route of mitochondrial targeting as a practical approach for cancer therapy, which can be achieved by optimizing the delivery method.

l-carnitine protects rat hepatocytes from oxidative stress induced by T-2 toxin.

CONTEXT: Oxidative stress and mitochondrial dysfunction are thought to be the main mechanism of T-2 toxin toxicity. T-2 toxin is the most potent trichothecene mycotoxin which is present in agricultural products. L-carnitine, besides its anti-oxidative properties, facilitates the transportation of long-chain fatty acids in to mitochondrial matrix. OBJECTIVE: In this study we tested whether L-carnitine, an antioxidant and a facilitator for long-chain fatty acid transportation across mitochondrial membranes, could protect rat hepatocytes against toxicity induced by T-2 toxin. MATERIALS AND METHODS: L-carnitine in low and high doses (50 and 500 mg/kg) was administered for five consecutive days to male Wistar rats. Hepatocytes were isolated and freshly exposed to appropriate concentration of T-2 toxin for 2 h followed by oxidative stress and cell death evaluations. RESULTS: Glutathione depletion, ROS overproduction and mitochondrial membrane potential collapse were determined under T-2 toxin exposure. Pretreatment with L-carnitine particularly at high-dose reduced toxicity and prevented the hepatocytes from abnormal caspase-3 activity and apoptosis. CONCLUSION: Low toxicity of L-carnitine and its mitochondrial protective effects promises an effective way to reduce or prevent the toxicity induced by certain environmental pollutants, including T-2 toxin.

Determination of the mutagenicity potential of dillsun herbal medicine by single cell gel electrophoresis in rat hepatocytes.

BACKGROUND: Traditional medicines are among the oldest medicines and their extensive use in the recent years reflects the public's interest in alternatives to conventional medicine. OBJECTIVES: The aim of this study was to investigate the genotoxicity of Dillsun herbal medicine in DNA damage of rat hepatocytes compared to sodium dichromate using a comet assay technique. MATERIALS AND METHODS: Male Wistar rats were caught and their liver was washed with a perfusion buffer, followed by another wash with collagenase buffer. Hepatocytes were isolated and transferred on to a petri dish which contained a washing buffer. Hepatocytes were then separated and the cells were filtered and centrifuged at 1500 rpm for 3 minutes. The hepatocytes were counted using neubauer slides and kept in a bioreactor for 30 minutes. Cells were then exposed to different doses of Dillsun such 0.2, 1, 2.5, 5 and 10 mg/mL. Sodium dichromate was the positive control and incubated buffer was used as a negative control. Cell suspensions were placed on slides pre-coated with low melting point agarose and were covered with agarose gel. Agarose gels were then lysed and electrophoresis was done, followed by neutralization and staining. Slides were analyzed by fluorescence microscopy. The size and extent of DNA damage visualized by this technique was evaluated by examining cells. Migration behavior was classified according to the Kobayashi pattern. RESULTS: The results indicated that with an increase of Dillsun dose, the mutagenicity index slightly increased but compared to the positive control, there were significant differences, which suggests that the crude extract of Dillsun in vitro did not have mutagenic effects. CONCLUSIONS: In conclusion the results showed that Dillsun has no mutagenic effects when compared to the positive control. Although by increasing the Dillsun dose, DNA damage also increased but this increase was not significant.

Determination of the mutagenicity potential of supermint herbal medicine by single cell gel electrophoresis in rat hepatocytes.

PURPOSE: The increasing use of herbal drugs and their easy availability have necessitated the use of mutagenicity test to analyze their toxicity and safety. The aim of this study was to evaluate the genotoxicity of Supermint herbal medicine in DNA breakage of rat hepatocytes in comparison with sodium dichromate by single cell gel electrophoresis technique or comet assay. METHODS: Hepatocytes were prepared from male wistar rats and were counted and kept in a bioreactor for 30 minutes. Then cells were exposed to the Supermint herbal medicine at doses of 125, 250 and 500 µl/ml. Buffer 4 (incubation buffer) and sodium dichromate were used as negative and positive control for one hour respectively. Then cell suspension with low melting point agarose were put on precoated slides and covered with agarose gel. Then lysing, electrophoresis, neutralization and staining were carried out. Finally the slides were analyzed with fluorescence microscope. The parameter under this analysis was the type of migration which was determined according to Kobayashi pattern. RESULTS: With increased dose of Supermint herbal medicine the DNA damage was slightly increased (P<0001). Conlusion: In overall compared to the positive control significant differences is observed which convinced that the crude extract of Supermint in vitro did not have mutagenic effect. Conlusion: In overall compared to the positive control significant differences is observed which convinced that the crude extract of Supermint in vitro did not have mutagenic effect.

Determination of the Mutagenicity Potential of Sankol Herbal Medicine by Single Cell Gel Electrophoresis in Rat Hepatocytes in Comparison With H2O2.

BACKGROUND: The increasing use of herbal drugs and their ease of accessibility and availability have necessitated the use of mutagenicity test to analyze their toxicity and safety. OBJECTIVES: This study aimed to evaluate the genotoxicity of Sankol herbal medicine in DNA breakage of rat hepatocytes in comparison with H2O2 by single cell gel electrophoresis technique or comet assay. MATERIALS AND METHODS: In the current study hepatocytes were prepared from male wistar rats. Hepatocytes cells were counted and kept in a bioreactor for 30 minutes,then cells were exposed to Sankol herbal medicine at doses of 100, 200 and 400 µl/ml. Buffer 4 (incubation buffer) and H2O2 were used for one hour as negative and positive control respectively. After 30 minutes cell suspension with low melting point agarose was put on precoated slides and covered with agarose gel. Then lysing, electrophoresis, neutralization and staining were carried out. Finally the slides were analyzed by fluorescence microscope. The parameter under this analysis was the type of migration which was determined according to Kobayashi pattern. RESULTS: Results of the study indicated that by increasing the dose of Sankol herbal medicine, the DNA damage slightly increased (P < 0001). CONCLUSIONS: In overall compared to the positive control, significant differences were observed which indicated that the crude extract of Sankol in vitro did not have mutagenic effect.