In Situ Localization of Nonenzymatic Peroxidase‐Like Activity of Tissue‐Bound Transition Metals

Hematopathology in Sprague-Dawley rats following sub-chronic topical application of para-phenylenediamine

The aim of the present study was to analyze the hematological profile of male SD rats treated topically with aqueous solution of para-phenylenediamine (PPD), a component of almost all hair dye formulations. The rats were painted with different concentration of PPD (0, 1, 2 and 3 mg Kg(-1) Day(-1)) for 90 days and then sacrificed. The hematological profile indicated severe anemia characterized by significant (p < 0.05, 0.001) reduction of total RBC count (59%), packed cell volume (PCV, 50%) and haemoglobin level (70%) in the peripheral blood of PPD treated animals when compared to control group. The leucocytes profile exhibited an overall elevation of around twofold as compared to the control group with significant lymphocytosis (44.4%) and a higher percentage of blast cells (8.5%) as well as smudge (10.3%) and hairy cells (6.2%) in the peripheral blood of treated animals. Histopathological examination of spleen from treated rat's exhibit red pulp congestion, expansion of the germinal centre, hyperplasia of the membrane capsule and extensive accumulation of hemosidderin pigments in the red pulp of the spleen. Overall this study indicated an abnormal pathophysiological condition indicating adverse effect of PPD in the treated animal groups. The risk assessment of hair dye formulation needs to be reviewed in view of widespread usage of paraphenylenediamine in almost all hair dye formulation.

Cisplatin-Induced Hepatotoxicity Is Enhanced by Elevated Expression of Cytochrome P450 2E1

In this study, the possible potentiation of cisplatin-induced hepatotoxicity by cytochrome P450 2E1 (CYP2E1) was examined both in vitro and in vivo. Transfected HepG2 cells expressing CYP2E1 (E47 cells) and not expressing CYP2E1 (C34 cells) were used as an in vitro model, and mice drinking 2% acetone for 7 days to induce CYP2E1 were used as an in vivo model. Exposure of E47 cells to cisplatin caused a much greater loss of cell viability, more striking depletion of reduced glutathione (GSH), and higher reactive oxygen species (ROS) production as compared with C34 cells. The prooxidant L-buthionine-[R,S]-sulfoximine (BSO), which depletes GSH, enhanced cisplatin-induced loss of cell viability, whereas the antioxidant glutathione ethyl ester, or the iron chelator deferoxamine mesylate (DFO) protected against the cisplatin-induced loss of E47 cell viability. Diallyl sulfide (DAS), an inhibitor of CYP2E1, also protected against the cisplatin toxicity in the E47 cells. After being injected with cisplatin (ip, 45 mg/kg), mice drinking 2% acetone with increased CYP2E1 levels exhibited elevated levels of serum ALT and AST, liver caspase-3 activity and positive staining of TUNEL increased, and histopathology indicated the presence of necrotic foci in livers of acetone plus cisplatin-treated mice. Lipid peroxidation and protein oxidation as indicated by carbonyl formation, staining of 3-nitrotyrosine (3-NT) and iron were higher in the cisplatin plus acetone group, compared with cisplatin alone group. Both in vitro and in vivo results indicate that elevated CYP2E1 enhances cisplatin-induced hepatotoxicity, and the mechanism may involve increased production of ROS and oxidative stress.