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Ionic mechanisms of cell death in an in vitro ischemia model
Author(s) -
Yao Hang,
Xiang Gu,
Wang Juan,
Haddad Gabriel
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb121-c
Subject(s) - excitotoxicity , propidium iodide , penumbra , acidosis , chemistry , programmed cell death , ischemia , hypoxia (environmental) , glutamate receptor , pi , apoptosis , medicine , biophysics , endocrinology , biochemistry , biology , oxygen , organic chemistry , receptor
To simulate the cell injury/death in the ischemic penumbra, we have developed an in vitro ischemic solution (IS) that approximates the solution that bathes the peri‐infarct tissue. IS is composed of low O 2 (1.5%), low glucose (3 mM), low pH (6.4), excitotoxic levels of glutamate (100 μM), and ionic alterations (high K + , 64 mM, low Na + , 51 mM, low Ca 2+ , 0.13 mM, low Cl − , 77.5 mM). Using organotypic hippocampal slice cultures and propidium iodide (PI) uptake measurements, we have examined cell injury/death following treatment by IS or IS without ion shifts (IS ‐WIS : K + , 3 mM, Na + , 150 mM, Ca 2+ , 1.3 mM, Cl − , 135 mM). Our data show that, after 4 hours of treatment, the mean fluorescence intensity of PI uptake in the IS ‐WIS group was about ~2x higher in the CA1 region (143±17, n=12 vs 67±5, n=36, p<0.0001), 2.3x higher in the CA3 region (149±17, n=12 vs 65±6, n=36, p<0.0001), and 1.6x higher in the DG region (118±11, n=12 vs 72±7, n=36, p = 0.002) when compared with the IS‐treated group. However, modifying IS by restoring only Ca 2+ and Cl − back to normal (Ca 2+ , 1.3 mM, Cl − , 135 mM) did not cause the aforementioned alterations. These results suggest that 1) the final outcome of multiple ion alterations may not be harmful when combined with hypoxia, acidosis and excitotoxicity; and 2) high K + and/or low Na + play a role in alleviating IS‐induced cell injury and death. This project was supported by NIH PO1 HD 32573, NIH RO1 HL 66237.