Authors: Hasan Esen Fatih Erdi Bulent Kaya Bahadır Feyzioglu Fatih Keskin Lutfi Saltuk Demir
Publish Date: 2014/11/13
Volume: 121, Issue: 3, Pages: 451-458
Abstract
Thioredoxin Trx is a redox active protein that regulates several physiological and biochemical functions such as growth apoptosis and cellular defense The function of Trx itself is regulated by thioredoxin reductase TrxR Studies performed in a variety of human primary tumors have shown that thioredoxin reductase 1 TrxR1 is overexpressed in tumoral tissues compared with corresponding normal tissues This study was designed to determine the expression of TrxR1 in astrocytoma tissues of different World Health Organization WHO grades grade I–IV The proliferative Ki67 and apoptotic indices of the specimens were also investigated for correlation analysis Astrocytoma tissues were extracted from the histopathological specimens of 40 patients These samples included seven histologically normal brain tissues that served as a control group and ten tumoral samples for each grade of astrocytoma grade I–IV The histologically normal brain tissues were obtained from the nontumoral portions of the pathological specimens of grade I 2 cases grade II 2 cases grade III 2 cases and grade IV 1 case astrocytomas TrxR1 expression was evaluated using quantitative reverse transcription polymerase chain reaction qRTPCR and immunostaining The proliferative and apoptotic indices of the specimens were investigated by Ki67 immunostaining and TUNEL assay respectively TrxR1 expression as assessed by qRTPCR increased significantly with astrocytoma grade p = 001 The immunostaining intensity of TrxR1 in grade IV astrocytomas was significantly greater than that in the control tissue and all other astrocytoma grades p 0001 Similarly immunostaining intensity of TrxR1 in the grade III astrocytomas was significantly greater than that in the control group and grade I astrocytomas p 0001 All astrocytoma tissues showed more intense staining in ascending grades but the differences between grade I and the control grade II and the control grades II and I grades III and II were not statistically significant p 005 Ki67 index values increased significant in accordance with grade progression p = 001 The apoptotic index values were not significantly different in any group p 005 however the differences between grade IV and the control and between grades IV and I were statistically significant p 005 Expression of TrxR1 as assessed by both qRTPCR and immunostaining correlated highly with both the astrocytoma grade and Ki67 index
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