Abstract
Gap junction (GJ) mediated X-ray bystander effect has been examined by using lindane (γ-BHC), an inhibitor of the GJ function. X-ray microbeam with a diameter of 100 micrometer was available from a micro-capillary tube installed in a table-top X-ray fluorescence analyzer for local specimen area (XGT-2700, HORIBA Ltd.). First, the concentration and the timing of the administration of lindane were determined using human normal skin fibroblast NB1RGB cells. The GJ function restraint by lindane was detected with Lucifer Yellow Transfer method. The results showed that 1) the GJ function was completely restrained by 2 hr incubation with 100 μM of lindane, and 2) the restraint by lindane begins to release immediately after removal of the reagent and fully recovered after 4 hrs. These results suggest that lindane is a useful tool for the examination of time-dependent progression of the bystander effects via GJ. Second, a bystander effect was estimated by p53 expression area which was observed using the fluorescent antibody technique after 6hr incubation from irradiation. The expression area was limited to the beam diameter by the addition of 100 μM lindane. The result indicated the important role of GJ in the bystander effect. The progression of the bystander effect after irradiation is under examination by varying the administration timing or the removal timing of lindane.
