comparison of hepatocyte cytotoxic mechanisms for docetaxel and PLGA-docetaxel nanoparticls

Docetaxel [DTX] is one of the most widely used drugs in oncology due to its high efficacy against several cancers. Though, its routine clinical administration, formulated in tween 80, causes serious side effects. Polylactide-co-glycolide [PLGA], biodegradable polyester synthesized and approved for human use, is employed to overcome these problems. In this investigation, we compare the cytotoxic mechanisms of DTX and PLGA-DTX in isolated rat hepatocytes. Cytotoxicity of DTX and PLGA-DTX were associated with reactive oxygen species formation, activation of caspases cascade, collapse of mitochondrial membrane potential [MMP], lysosomal membrane leakiness and ATP depletion. Our results also showed that CYP2E1 is involved in the oxidative stress cytotoxicity mechanism and both drugs are detoxified via phase II metabolic methylation. Furthermore, we concluded that PLGA-DTX is bioactivated by GSH. It could also potentiate hepatocyte toxicity through a mitochondrial/lysosomal toxic cross-talk. In addition to these observed differences, it is likely that mode of hepatocyte membrane penetration is different between these compounds

Chlorpyrifos toxicity in mouse cultured cerebellar granule neurons at different stages of development: additive effect on glutamate-induced excitotoxicity

Objective: Chlorpyrifos [CPF] is a neurotoxic organophosphorus [OP] insecticide. Its mechanism of action includes oxidative stress, excitotoxicity, and inhibition of the acetylcholinesterase enzyme [AChE]. The aim of the present study is to investigate CPF toxicity in mature and immature cerebellar granule neurons [CGNs], as well as its effect on glutamate induced excitotoxicity

Materials and Methods: this study was an in vitro experimental study performed on mice cultured CGNs. Immature and mature neurons were exposed to different concentrations of CPF [1-1000 [micro]M] and glutamate [10-600 [micro]M] for 48 hours after which we used the MTT assay to measure cytotoxicity. Immature neurons had exposure to CPF for 5 days in order to evaluate the cytotoxic effect on developing neurons. Mature neurons received sub-lethal concentrations of CPF [10, 100 [micro]M] combined with different concentrations of glutamate. AChE activity and reactive oxygen species [ROS] generation were assessed after treatments

Results: immature CGNs had increased sensitivity to CPF toxicity compared to mature neurons. We observed significantly greater ROS production in immature compared to mature neurons, however AChE activity was more inhibited in mature neurons. Although CPF toxicity was not well correlated with AChE inhibition, it correlated well with ROS production. Glutamate toxicity was potentiated by sub-lethal concentration of CPF, however glutamate induced ROS production was not affected. The results suggested that CPF potentiated glutamate toxicity by mechanisms other than oxidative stress

Conclusion: CPF toxicity differed in mature and immature neurons. Potentiated glutamate toxicity by CPF implied that CPF exposure might be a risk factor for neurodegenerative disease

Cytotoxic effect of Iranian vipera lebetina snake venom on HUVEC cells

Envenomation by heamotoxic snakes constituted a critical health occurrence in the world. Bleeding is the most sever consequence following snake bite with viperid and crothalid snakes. It is believed that the degradation of vascular membrane caused hemorrhage; in contrast, some suggested that direct cytotoxicity has role in endothelial cell disturbances. This study was carried out to evaluate the direct toxicity effect of V. lebetina crude venom on Human Umbilical Vein Endothelial Cells [HUVECs]. The effect of V. lebetina snake venom on HUVECs growth inhibition was determined by MTT assay and neutral red uptake assay. The integrity of cell membrane through LDH release was measured with the Cytotoxicity Detection Kit. Morphological changes of endothelial cells were also evaluated using a phase contrast microscope. In MTT assay, crude venom showed a cytotoxic effect on endothelial cells which was confirmed by the effect observed with neutral red assay. Also, crude venom caused changes in the integrity of cell membrane by LDH release. The morphological alterations enhanced in high concentration results in total cells number reduced. V. lebetina venom showed potential direct cytotoxic effects on human endothelial cells in a manner of concentration-dependent inhibition

Uranyl acetate induces oxidative stress and mitochondrial membrane potential collapse in the human dermal fibroblast primary cells

Cytotoxicity of depleted uranium, as a byproduct of military has been came to spotlight in recent decades. DU is known as a chemical rather than radioactive hazard and efforts to illustrating its mechanism is undergo, but the precise complete molecular mechanisms are still unclear. Recent studies showed that uranium induces biological changes in many different target tissues, such as the kidney, brain and skin. The aim of this study was to assess the impact of depleted uranium exposure at the cellular level in the human dermal fibroblast primary cells. The human dermal fibroblast primary cells incubated with different concentration [250-750 microM] of depleted uranium. Cytotoxicity and mitochondrial function in this cell lines were determined with the LDH leakage assay and the MTT test respectively. MDA levels were measured for determination of Lipid peroxidation in DU treated cells. Besides glutathione depletion and apoptosis phenotype detection were also assessed to complete the mechanistic screening. Results showed that the cell viability ameliorates in concentration and time dependent manners following in 24, 48 and 72 h incubation with DU. Moreover the significant increase in lipid peroxidation and significant decrease in cellular GSH recorded in DU treated human dermal fibroblast primary cells suggesting the preoxidant effect of uranyl ions. Cytoprotective effects of N-acetylcysteine [NAC] and dramatic decrease of cell viability in buthionin sulfoxamid [BSO] pretreated cells indicated the possibility of a critical role for glutathione system in DU detoxification. Death pattern, in fibroblast cells following DU treatment was varied from apoptosis to necrosis while the time and concentration increased. Since ROS formation is the initiation step for cell apoptosis, the present studies suggest Uranyl-induced toxicity in the human dermal fibroblast primary cells originated from oxidative stress and lead to occurrence of programmed cell death

T2-toxin hepatotoxicity in the in situ rat liver model

T-2 toxin, a trichothecene mycotoxin, is considered to be one of the most toxic compounds that are produced by molds, particularly the Fusarium species. Fusarium species have been recognized as a great agricultural problem. They occur worldwide on a variety of plant hosts and cereal grains. The aim of this study was to investigate T-2 toxin-induced liver injury using in situ perfused rat liver. The in situ perfused rat liver [IPRL] was chosen because it permits studies of liver function in a system that resembles normal physiology. Elevation of aminotransferase activities have shown to be a good indicator of hepatocellular damage. In addition, glutathione levels have also shown to be an indicator of liver damage through lipid peroxidation. Male Sprague-Dawley rats [6-8 weeks] weighing 250-300 g were used in this study. They were randomly divided into 5 groups of 3-4 rats per cage. In group 1, liver was perfused by Krebs-Henseleit buffer alone [Control]. Groups 2-5 received different concentration of T-2 toxin [4, 9, 21, 43 [rho]mol/L] in Krebs-Henseleit buffer and biochemical changes in the liver were examined within 2 h. There was a significant increase in both ALT and AST activity in all dose levels compared with the control group [p<0.01 and p<0.05]. T-2 toxin treatment enhanced lipid peroxidation in the liver, as indicated by the increased MDA content in liver homogenates. The MDA level was maximal 2 h after the T-2 toxin challenge [p<0.01 and p<0.05]. The results also show that T-2 toxin causes an increase in lipid peroxidation while causing a decrease in glutathione [GSH] content in bile secretion [p<0.01]. This result suggests that both lipid peroxidation and glutathione [GSH] depletion play a role in T-2 toxin liver induced damages