Oxidative injury is involved in fipronil-induced G2/M phase arrest and apoptosis in Spodoptera frugiperda (Sf9) cell line.

摘要

Fipronil (FPN) is a phenylpyrazole insecticide acted on insect gamma-aminobutyric acid (GABA) receptors. Although action of FPN is restricted on insect neuronal or muscular transmitter system, a few studies have assessed the toxicity and its underlying mechanisms on the insect reproduce. To determine whether FPN-induced reproductive hazards on insect, we used the insect cells (Sf9) derived from Spodoptera frugiperda pupal ovarian as an in vitro model. FPN was cytotoxic to Sf9 cells with a time- and concentration-dependent manner. After Sf9 cells exposure to FPN (400 micro g/mL) for 48 h, flow cytometry analysis showed FPN-induced Sf9 cells G2/M phase arrest, the percentage of G2/M phase cells evidently increased from 57.08+or-0.29% to 90.48+or-1.75%, whilst, the proportion of apoptotic cells are also significantly increased from 4.48+or-0.52% to 19.75+or-1.01%. Morphological observation found FPN treated cells showed typical apoptosis morphological changes including cell swelling, apoptotic bodies and small fragments. Western blotting revealed Cdk1, cyclin A, cyclin B1 and Bcl-2 were markedly down-regulated, and cytosolic Cyt c, caspase-3 expressions were significantly augmented in FPN-treated Sf9 cells. Intracellular biochemical assays testified that FPN-induced G2/M cell cycle arrest and apoptosis involved in increase of ROS generation, especially OH and depleted GSH level and Na+-K+-ATPase, Ca2+-Mg2+-ATPase activities. The results provide a new point of view to study the toxicology and mode of action of insecticide on cellular level.