The biological activities of C(60)-bis(N,N-dimethylpyrrolidinium iodide), a water-soluble cationic fullerene derivative, on human promyeloleukaemia (HL-60) cells were investigated. The pyrrolidinium fullerene derivative showed cytotoxicity in HL-60 cells. The characteristics of apoptosis, such as DNA fragmentation and condensation of chromatin in HL-60 cells, were observed by exposure to the pyrrolidinium fullerene derivative. Caspase-3 and -8 were activated and cytochrome c was also released from mitochondria. The generation of reactive oxygen species (ROS) by the pyrrolidinium fullerene derivative was observed by DCFH-DA, a fluorescence probe for the detection of ROS. Pre-treatment with alpha-tocopherol suppressed cell death and intracellular oxidative stress caused by the pyrrolidinium fullerene derivative. The apoptotic cell death induced by the pyrrolidinium fullerene derivative was suggested to be mediated by ROS generated by the pyrrolidinium fullerene derivative.
Irradiation by light emitting diode (LED) promotes fibroblast proliferation and wound healing. However, its mechanism is still unknown. The purpose of this study was to clarify the mechanism of fibroblast proliferation by LED irradiation. Cultured NIH3T3 fibroblasts from normal mice were irradiated by LED with a center wavelength of 627 nm. LED irradiation was performed with an energy density of 4 J/cm(2), at subculture and 24 h later. The expression of several growth factors and their receptors was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR): platelet-derived growth factor (PDGF)-A, PDGF-B, and PDGF-C, transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), PDGF-alpha receptor, and TGF-beta receptor. Then, the activation of the extracellular signal-regulated kinase (ERK) pathway was examined by Western blotting with and without the PDGF receptor inhibitor. LED irradiation induced cell growth of NIH3T3 fibroblasts. The expression of PDGF-C had significantly increased in the irradiated group (P < 0.01). Although strong activation of the ERK pathway was observed in the irradiated group, its activation was completely suppressed by the PDGF receptor inhibitor. We concluded that LED irradiation promotes fibroblast proliferation by increasing autocrine production of PDGF-C and activating the ERK pathway through phosphorylation of the PDGF receptor.
A new series of binuclear copper(II) complexes with 1,3-bis(hydroxymethyl)-2-imidazolidinethione, [Cu(RCOO)(HL1)]2 (where R = CH3 (1), C6H5 (2), 2-CH3C6H4 (3), 4-CH3C6H4 (4), 2-ClC6H4 (5), and 2-BrC6H4 (6)), and with 1-hydroxymethyl-3-methyl-2-imidazolidinethione, [Cu(RCOO)(L2)]2 (where R = CH3 (7), 2-CH3C6H4 (8), and 4-CH3C6H4 (9)), have been prepared. The magnetic susceptibility data of complexes 1—9 conform to the usual dimer equation with the −2J values ranging from 227 to 992 cm−1. Crystal structure analyses of 3, 4, 7, and 9 revealed that two copper atoms are linked by two alkoxo-bridges with separations of 3.015(3)—3.069(3) Å in each complex. The coordination around each copper atom of the complexes is essentially a square planar configuration with one sulfur and two alkoxo-oxygen atoms of HL1 or L2 and one oxygen atom of carboxylates. Each alkoxo-group asymmetrically bridges with the Cu1–O1 bonds (1.90—1.92 Å), which are shorter than the Cu1′–O1 bonds (1.93—1.97 Å). The −2J values for complexes 3, 4, 7, and 9 are much better correlated with the Cu1′–O1 bond distances than with the alkoxo-bridging Cu1–O1–Cu1′ angles.
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