Mitochondrial electron-transport-chain inhibitors of complexes I and II induce autophagic cell death mediated by reactive oxygen species

Chenopodium album seed extract-induced sperm cell death: exploration of a plausible pathway

BACKGROUND

This study was conducted for to explore the plausible pathway of Chenopodium album seed extract (CAE)-mediated sperm cell death.

STUDY DESIGN

The role of CAE for its spermicidal action was assessed by (a) measuring lipid peroxidation, protein carbonyl content and intracellular glutathione content in CAE exposed sperm cells; (b) assaying antioxidant enzymes like catalase and superoxide dismutase (SOD); (c) analyzing protein expressions by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis; (d) fluorimetric measurement of intracellular H(2)O(2) level and generation of reactive oxygen species (ROS) in CAE-treated sperm cells; and (e) DNA ladder formation study.

RESULTS

CAE-induced sperm death is due to (a) lipid peroxidation of the sperm cell membrane, oxidation of some critical cellular proteins and depletion of intracellular reduced gluthathione, indicating production of ROS; (b) activation of Mn-SOD and inactivation of catalase favoring endogenous accumulation of H(2)O(2); (c) generation of O(2)(*-) at an enhanced rate during oxidative stress as evidenced by increased Mn-SOD activity and protein expression; (d) accumulation of ROS in spermatozoa reflected in the fluorimetric experiments; and (e) increased production of O(2)(*-) and H(2)O(2) induced apoptosis-like death in sperm cells as observed by DNA ladder formation.

CONCLUSION

The sperm death mediated by CAE is due to oxidative damage of cellular macromolecules by in situ generation of ROS.

In vitro methods to monitor autophagy in Lepidoptera

Autophagy is attracting growing interest, especially in relation to increasing evidence of the importance of autophagic processes in animal development, as well as in human cancer progression. In holometabolous insects (i.e., that undergo four distinct life cycle stages, including embryo, larva, pupa and imago), such as flies, butterflies, bees and beetles, autophagy has been found to play a fundamental role in metamorphosis, and given the high degree of conservation of the genes and the basic mechanisms of autophagy, attention to these relatively simple models has increased significantly. Together with Drosophila, Lepidoptera larvae are among the most common invertebrate models in studies concerning the protective action of starvation-induced autophagy or the possible role of autophagy as a programmed cell death process. In this chapter, we provide experimental methods developed for, or applicable to, the study of the autophagic process in the IPLB-LdFB cell line derived from the fat body of the caterpillar of the gypsy moth, Lymantria dispar.