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Mercury (Hg) is one of the universal environmental pollutants and is responsible for various organ pathophysiology including oxidative stress-induced hepatic disorders. In the present study, we aimed to explore the protective role of glycine in Hg-induced cytotoxicity and cell death in murine hepatocytes. Exposure of mercury (20 μM), in the form HgCl2 for 1 h, significantly enhanced the ALT and ALP leakage, increased reactive oxygen species production, reduced cell viability and distorted the antioxidant status of hepatocytes. Flow cytometric analyses shows that Hg-induced apoptotic death in hepatocytes. Mechanism of this pathophysiology involves reduced mitochondrial membrane potential, variations in Bcl-2/Bad proteins, activation of caspases and cleavage of PARP protein. In addition, Hg distinctly increased NF-κB phosphorylation in association with IKKα phosphorylation and IκBα degradation. Concurrent treatment with glycine (45 mM), however, reduced Hg-induced oxidative stress, attenuated the changes in NF-κB phosphorylation and protects hepatocytes from Hg-induced apoptotic death. Hg also distinctly increased the phosphorylation of p38, JNK and ERK mitogen-activated protein kinase (MAPKs). Glycine treatment suppressed these apoptotic events, signifying its protective role in Hg-induced hepatocyte apoptosis as referred by reduction of p38, JNK and ERK MAPK signaling pathways. Results suggest that glycine can modulate Hg-induced oxidative stress and apoptosis in hepatocytes probably because of its antioxidant activity and functioning via mitochondria-dependent pathways and could be a beneficial agent in oxidative stress-mediated liver diseases.

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Doxorubicin (Dox) is an effective anthracycline antitumour drug although its clinical efficacy is restricted because of several acute and chronic side effects. It has been suggested that Dox-induced anticancer effect and neurotoxicity do not follow identical mechanism. The present study has been carried out to investigate the neuroprotecive role of a 43-kD protein (Cajanus indicus (CI) protein) against Dox-induced oxidative impairment and brain tissue damage. Administration of Dox (25 mg/kg body weight) increased reactive oxygen species (ROS) production, altered neuro antioxidant status, activities of brain specific coenzymes (like acetyl coenzyme, monoamine oxidase, etc.), ATPases (like Na(+)/K(+), Ca(2+), etc.) and brain biogenic amines levels. Signal transduction studies showed that Dox markedly decreased mitochondrial membrane potential, disturbed Bcl-2 family protein balance, enhanced cytochrome c release in the cytosol, increased levels of Apaf1, caspase-9/3, cleaved PARP protein and ultimately led to apoptotic cell death. In addition, Dox markedly increased nuclear factor kappa B (NF-κB) nuclear translocation in association with IKKα/β phosphorylation and IκBα degradation. Post-treatment with CI protein (3 mg/kg body weight, once daily for next 4 days), however, reduced Dox-induced oxidative stress, attenuated the nuclear translocation of NF-κB and protected the brain tissue from Dox-induced apoptotic death. Histological studies also support these experimental findings. Results suggest that CI protein might act as a beneficial agent against Dox-induced neuronal dysfunctions.