Nonylphenol-induced thymocyte apoptosis involved caspase-3 activation and mitochondrial depolarization.
Although the effect of 4-nonylphenol on cells of immune system have long been recognized, little is known about the effect of 4-nonylphenol on the induction of apoptosis and related signaling events in the lymphoid cells. In the present study, we used cultured thymocytes of mice to investigate the ability of 4-nonylphenol to induce the apoptosis of thymocytes and to explore the role of signal transduction pathway leading to apoptosis. The results showed that the cytotoxic effects of 4-nonyphenol involved DNA fragmentation (DNA ladder), characteristic of apoptosis. Staining of 4-nonyphenol-treated thymocytes with DNA-binding fluorochrome Hoechst 33258 showed the typical apoptotic nuclei condensation and fragmentation of chromatin. The rates of apoptosis of the 4-nonylphenol-treated thymocytes increased significantly at 4 and 6 h, which were determined by analysis of hypodiploid cells and FITC-Annexin V and PI double staining. Flow cytometer analysis also revealed that the loss of mitochondrial membrane potential and increased activity of caspase-3 occurred concomitantly with the onset of 4-nonyphenol-induced apoptosis. Furthermore, a caspase-3 inhibitor, z-DEVD-fmk protected thymocytes from apoptosis induced by 4-nonyphenol. These results suggest that 4-nonylphenol induces thymocyte apoptosis via caspase-3 activation and mitochondrial depolarization.
Yao
Genhong
G
Jiangsu Province Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China.
Yang
Lingsong
L
Hu
Yali
Y
Liang
Jun
J
Liang
Junfeng
J
Hou
Yayi
Y
D000818:Animals; D017304:Annexin A5 / Q000032:analysis; D017209:Apoptosis; D053148:Caspase 3; D053181:Caspase 8; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D053938:DNA Fragmentation; D016650:Fluorescein-5-isothiocyanate / Q000032:analysis; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects*; D010636:Phenols / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000201:enzymology; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
D017304:Annexin A5; D061945:Caspase Inhibitors; D010636:Phenols; D011480:Protease Inhibitors; C025256:nonylphenol; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases; D016650:Fluorescein-5-isothiocyanate