tacrolimus and pyrazolanthrone

Topics: Anthracenes; Antioxidants; Calcineurin; Cell Line; Cyclosporine; Granulocytes; Humans; Imidazoles; Inhibitory Concentration 50; JNK Mitogen-Activated Protein Kinases; Mycotoxins; Neurotoxins; Neutrophils; p38 Mitogen-Activated Protein Kinases; Pyridines; Reactive Oxygen Species; Tacrolimus; Vitamin E

We previously demonstrated that FK506, a generally applied immunosuppressant in organ transplantation, could promote peripheral nerve regeneration through reducing scar formation. However, little is known about how FK506 reduces scar formation. Herein we investigated the influence of FK506 on fibroblast proliferation and its correlation with scar formation after sciatic nerve injury in rats, and further explored the effect of FK506 on fibroblast proliferation and apoptosis in vitro. Masson staining and immunohistochemistry revealed that scar area and fibroblast number in the nerve anastomosis of sciatic nerve-injured rats were significantly reduced after FK506 administration. The scar area had a significant positive correlation with the fibroblast number, as detected by linear correlation analysis. CCK-8 assay and flow cytometry indicated that FK506 also inhibited proliferation and induced apoptosis of fibroblasts in vitro. It was primarily phosphorylation of JNK and ERK that were activated during the apoptosis of fibroblast. Pretreatment of cells with JNK inhibitor, SP600125, or ERK inhibitor, PD98059, could inhibit FK506-induced fibroblast apoptosis, respectively. Moreover, simultaneous application of both inhibitors had additive roles in cell protection from apoptosis. These results suggest that FK506-induced fibroblast apoptosis contributes to the suppression of fibroblast proliferation and then results in the reduction of scar formation in sciatic nerve-injured rat, and that JNK and ERK are involved in FK506-induced fibroblast apoptosis.

Topics: Anastomosis, Surgical; Animals; Anthracenes; Apoptosis; Caspase 3; Cell Proliferation; Cells, Cultured; Cicatrix; Cytochromes c; Cytoprotection; Extracellular Signal-Regulated MAP Kinases; Fibroblasts; Flavonoids; Immunosuppressive Agents; JNK Mitogen-Activated Protein Kinases; Male; Phosphorylation; Rats; Rats, Sprague-Dawley; Sciatic Nerve; Tacrolimus

Polychlorinated biphenyls (PCBs) are reported to induce the formation of reactive oxygen species (ROS) in human neutrophil granulocytes through the activation of the NADPH oxidase. The purpose of the present study is to elucidate the cellular mechanisms responsible for the activation of the NADPH oxidase after exposure to PCB. We have previously shown that PCB activates human neutrophil granulocytes through a calcium dependent activation of phospholipase D and/or phospholipase C, followed by the activation of protein kinase C. In the present study, pharmacological characterization of Aroclor (A) 1242-induced respiratory burst in human neutrophils was conducted by the use of enzymatic inhibitors. Pre-incubation with U0126, SB203580, SP600125, cyclosporin A and FK506 attenuated the A 1242-induced respiratory burst, measured by DCF-fluorescence, and luminol-amplified chemiluminescence. Our results show that the Erk1/2 kinases and p38MAPK/JNK are involved in ROS formation in neutrophils exposed to A 1242.

Topics: Anthracenes; Aroclors; Butadienes; Cyclosporine; Environmental Pollutants; Enzyme Activation; Enzyme Inhibitors; Humans; Imidazoles; Luminescent Measurements; NADPH Oxidases; Neutrophil Activation; Neutrophils; Nitriles; Pyridines; Respiratory Burst; Tacrolimus