Apoptosis

, Volume 17, Issue 5, pp 439–448

High cytosolic free calcium level signals apoptosis through mitochondria-caspase mediated pathway in rat eggs cultured in vitro

Authors

  • Anima Tripathi
    • Cell Physiology Laboratory, Biochemistry Unit, Department of ZoologyBanaras Hindu University
    • Cell Physiology Laboratory, Biochemistry Unit, Department of ZoologyBanaras Hindu University
Original Paper

DOI: 10.1007/s10495-012-0702-9

Cite this article as:
Tripathi, A. & Chaube, S.K. Apoptosis (2012) 17: 439. doi:10.1007/s10495-012-0702-9

Abstract

The present study was aimed to find out whether an increase of cytosolic free calcium level induces egg apoptosis through mitochondria-caspase mediated pathway. To increase cytosolic free calcium level and morphological apoptotic changes, ovulated eggs were cultured in Ca2+/Mg2+ free media-199 with or without various concentrations of calcium ionophore (0.5, 1, 2, 3, 4 μM) for 3 h in vitro. The morphological apoptotic changes, cytosolic free calcium level, hydrogen peroxide (H2O2) concentration, catalase activity, cytochrome c concentration, caspase-9 and caspase-3 activities and DNA fragmentation were analyzed. Calcium ionophore induced morphological apoptotic features in a concentration-dependent manner followed by degeneration at higher concentrations (3 and 4 μM). Calcium ionophore increased cytosolic free calcium level, induced generation of hydrogen peroxide (H2O2) and inhibited catalase activity in treated eggs. The increased H2O2 concentration was associated with increased cytochrome c concentration, caspase-9 and caspase-3 activities that resulted in the induction of morphological features characteristic of egg apoptosis. The increased caspase-3 activity finally induced DNA fragmentation as evidenced by TUNEL positive staining in calcium ionophore-treated eggs. These findings suggest that high cytosolic free calcium level induces generation of H2O2 that leads to egg apoptosis through mitochondria-caspase mediated pathway.

Keywords

Cytosolic free calciumHydrogen peroxideCytochrome cCaspases activityDNA fragmentationEgg apoptosis

Supplementary material

10495_2012_702_MOESM1_ESM.tif (267 kb)
Supplementary material 1 (TIFF 266 kb)

Copyright information

© Springer Science+Business Media, LLC 2012