Rotenone, a selective inhibitor of mitochondrial complex I, has been extensively studied on kinds of neuron and neuroblast in
Parkinson's disease. However, little is known about the potential mechanism of this promising botanical
insecticide upon insect cells. In the article, cell proliferation of two Lepidoptera cell lines, Spodoptera litura
SL-1 cells and Spodoptera frugiperda Sf9 cells, were all inhibited by
rotenone in a time- and dose-dependent manner. Typical necrotic characteristics of cell morphology and ultrastructure, such as plasma membrane collapses and organelle lyses, were all observed by transmission electron microscope and scanning electron microscope. Moreover, irregular
DNA degradation was also detected by
DNA gel electrophoresis and
Hoechst 33258 staining, while the typical apoptotic feature,
DNA ladder, hadn't been observed. Flow cytometric analysis showed that
rotenone-induced cell death of Sf9 and
SL-1 cells accompanied with the plasma membrane potential depolarization and mitochondrial membrane potential reduction. Furthermore, the activity of Na+-K+-
ATPase was detected in our study. In conclusion,
rotenone could cause
necrosis but not apoptosis in insect cells through a mitochondrial- and plasmic membrane-dependent pattern, which shed a light on the
rotenone-induced cytotoxicity on insects.