Plasma low-molecular-weight thiol/disulphide homeostasis as an early indicator of global and focal cerebral ischaemia

Objective: Recent studies have shown that cerebral ischaemia causes not only local, but also systemic oxidative stress. This leads to oxidation of thiol-containing compounds, including low-molecular-weight thiols (cysteine, glutathione, homocysteine and others). Therefore, the aim of this work was to verify the hypothesis that the thiol/disulphide homeostasis of low-molecular-weight thiols is disturbed in the early stages of cerebral ischaemia.

Methods: Two experimental rat models of ischaemia were used: a global model of vascular ischaemia (clamping the common carotid arteries?+?haemorrhage) and focal ischaemia (middle cerebral artery occlusion). The total levels of thiols and their reduced forms were measured before surgery and after 40 minutes of reperfusion (global) or 3?hours (focal) ischaemia.

Results: The global ischaemia model caused a marked (2.5–4 times, P?P?Discussion: These results suggest that plasma low-molecular-weight thiols are actively involved in oxidation reactions at early stages of cerebral ischaemia; therefore, their reduced forms or redox state may serve as a sensitive indicator of acute cerebrovascular insufficiency.     

Dynamic thiol/disulphide homeostasis as indicator of oxidative stress in automotive workers

Abstract

Purpose: To examine thiol-disulphide homeostasis auto painters.

Materials and methods: A total of 115 male workers, including 60 auto painters workers and 55 reference group, of the painting and assembly line units respectively, were included in the study. Thiol-disulphide parameters and ischaemia-modified albumin (IMA) of groups were determined. Urinary hippuric acid, (HA) phenol, hexanedione, trichloroacetic acid, arsenic and blood lead and manganese were analysed.

Results: The median urinary HA level was significantly higher in auto painters when compared to the reference group [(2461 (1212) vs. 520 (513) µgr/L), (p?<?0.001)] . The mean disulphide level [19.7 (4.3) vs 0.15.1(4.1) μmol/L, (p?<?0.001)], the disulphide/native thiol ratio [4.72 (1.47) vs. 3.13 (1.21, (p?<?0.001)] and the disulphide/total thiol ratio [4.31 (1.23) vs. 2.94 (1.06), (p?<?0.001)] were higher in auto painters when compared to the reference group. There was a statistically significant positive correlation between urinary HA and disulphide concentrations (r?=?0.536 and p?<?0.001), disulphide/native thiol ratio (r?=?0.564 and p?<?0.001) and the disulphide/total thiol ratio (r?=?0.564 and p?<?0.001) and IMA (r?=?0.396 and p?<?0.001).

Conclusion: The results presented in this study showed that oxidative stress can be associated with occupational exposure to toluene denoted by alteration of thiol disulphide homeostasis and ischaemia-modified albumin levels.