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Is the Cell Death in Mesial Temporal Sclerosis Apoptotic?
Author(s) -
Uysal Hilmi,
Cevik Isin Unal,
Soylemezoglu Figen,
Elibol Bulent,
Ozdemir Yasemin Gursoy,
Evrenkaya Tulay,
Saygi Serap,
Dalkara Turgay
Publication year - 2003
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1046/j.1528-1157.2003.37402.x
Subject(s) - tunel assay , apoptosis , programmed cell death , terminal deoxynucleotidyl transferase , in situ nick end labeling , biology , dna fragmentation , immunostaining , fragmentation (computing) , epilepsy , caspase , hippocampus , pathology , immunohistochemistry , caspase 3 , neuroscience , medicine , immunology , biochemistry , ecology
Summary: Purpose: Mesial temporal sclerosis (MTS) is characterized by neuronal loss in the hippocampus. Studies on experimental models and patients with intractable epilepsy suggest that apoptosis may be involved in neuronal death induced by recurrent seizures. Methods: We searched evidence for apoptotic cell death in temporal lobes resected from drug‐resistant epilepsy patients with MTS by using the terminal deoxynucleotidyl transferase (TdT) and digoxigenin‐11‐dUTP (TUNEL) method and immunohistochemistry for Bcl‐2, Bax, and caspase‐cleaved actin fragment, fractin. The temporal lobe specimens were obtained from 15 patients (six women and nine men; mean age, 29 ± 8 years ). Results: Unlike that in normal adult brain, we observed Bcl‐2 immunoreactivity in some of the remaining neurons dispersed throughout the hippocampus proper as well as in most of the reactive astroglia. Bax immunopositivity was increased in almost all neurons. Fractin immunostaining, an indicator of caspase activity, was detected in ∼10% of these neurons. Des pite increased Bax expression and activation of caspases, we could not find evidence for DNA fragmentation by TUNEL staining. We also could not detect typical apoptotic changes in nuclear morphology by Hoechst‐33258 or hematoxylin counterstaining. Conclusions: These data suggest that either apoptosis is not involved in cell loss in MTS, or a very slow rate of cell demise may have precluded detecting TUNEL‐positive neurons dying through apoptosis. Increased Bax expression and activation of caspases support the latter possibility.