Duprez, Jessica
[UCL]
Roma, Leticia P.
Close, Anne-Françoise
[UCL]
Jonas, Jean-Christophe
[UCL]
Aim/Hypothesis: Rat pancreatic islet cell apoptosis is minimal after prolonged culture in 10 mmol/l glucose (G10), largely
increased in 5 mmol/l glucose (G5) and moderately increased in 30 mmol/l glucose (G30). This glucose-dependent
asymmetric V-shaped profile is preceded by parallel changes in the mRNA levels of oxidative stress-response genes like
Metallothionein 1a (Mt1a). In this study, we tested the effect of ZnCl2, a potent inducer of Mt1a, on apoptosis, mitochondrial
oxidative stress and alterations of glucose-induced insulin secretion (GSIS) induced by prolonged exposure to low and high
vs. intermediate glucose concentrations.
Methods: Male Wistar rat islets were cultured in RPMI medium. Islet gene mRNA levels were measured by RTq-PCR.
Apoptosis was quantified by measuring islet cytosolic histone-associated DNA fragments and the percentage of TUNELpositive
b-cells. Mitochondrial thiol oxidation was measured in rat islet cell clusters expressing ‘‘redox sensitive GFP’’
targeted to the mitochondria (mt-roGFP1). Insulin secretion was measured by RIA.
Results: As observed for Mt1a mRNA levels, b-cell apoptosis and loss of GSIS, culture in either G5 or G30 vs. G10 significantly
increased mt-roGFP1 oxidation. While TPEN decreased Mt1a/2a mRNA induction by G5, addition of 50–100 mM ZnCl2 to the
culture medium strongly increased Mt1a/2a mRNA and protein levels, reduced early mt-roGFP oxidation and significantly
decreased late b-cell apoptosis after prolonged culture in G5 or G30 vs. G10. It did not, however, prevent the loss of GSIS
under these culture conditions.
Conclusion: ZnCl2 reduces mitochondrial oxidative stress and improves rat b-cell survival during culture in the presence of
low and high vs. intermediate glucose concentrations without improving their acute GSIS.
Bibliographic reference |
Duprez, Jessica ; Roma, Leticia P. ; Close, Anne-Françoise ; Jonas, Jean-Christophe. Protective Antioxidant and Antiapoptotic Effects of ZnCl2 in Rat Pancreatic Islets Cultured in Low and High Glucose Concentrations. In: PLoS ONE, Vol. 7, no.10, p. e46831 (2012) |
Permanent URL |
http://hdl.handle.net/2078.1/115000 |