Wednesday, 8 December 2010
The impact on inflammatory cytokine Production, apoptosis and G1
phases of human T lymphocyte induced by welding fume was investigated to discuss the effects of different ranges of particle size. The on-site dusts were collected by micro orifice uniform deposition impactor (MOUDI). Human T cell Line, Jurkat cell were treated by different sized dust particles which were classified to ten ranges of 8hr collected welding fumes under PM10
, prepared as 0.2 % buffered solutions, respectively. Inflammatory cytokine IL-6 and TNF-a production were measured at 24 hours by ELISA, and found both of the two were much higher by the particles smaller than 100 nm. Cell cycle and apoptosis were performed by flow cytometry. After 72hrs treatment, the viability decreased slightly related with the increasing ranges of size of the metal fume particles, counted by Trypan Blue stain and Propidium Iodide (PI) uptake, and apoptosis was estimated by cytosolic caspase 3 activation. The rates of apoptosis in each treatment were about 7~12% of the control. The increase rate of caspase 3, is according to the order of particle size reduction. Different size of welding fume particles also affect sub G1
cell cycle from 1~9 %, and 23~26% of G2
/M stage of the total cells. With the reduction of particle size, we observed a decrease tendency of sub G1 phase and an increase tendency of G2
/M phase in total cell percentages.
We conclude nano-sized particles in metal fume increases the production of inflammatory cytokines of T cell in a short term treatment, and makes cells arrested at G2/M phase and increases cell apoptosis in a long term exposure. Statistical results support the ultra-fine and nano-scale particles in welding fume cause larger effects on inflammatory cytokine production, Caspase 3 and G2/M arrest (r = -0.425, P= 0.019). Some metals, such as Manganese, Copper (Cu) and Nickel were analyzed by Atomic Absorption, only the concentrations of smaller sized Cu particles exhibited significant correlation with PI (r=-0.20, P=0.04). The mechanisms induce production of cytokines; apoptosis and G2 arrest with nano-sized welding fume remain to be clarified in future.