Measurement of some biochemical markers level in blood of mercury exposure workers

Other Title(s)

قياس مستوى بعض المؤشرات الكيموحيوية في نماذج دم العاملين المعرضين للزئبق

Dissertant

Hasan, Akram Umran

Thesis advisor

al-Azzawi, Hasan Fayyd Samir
Jumah, Nazim Hasan Haydar

University

University of Baghdad

Faculty

College of Science

Department

Biotechnology Department

University Country

Iraq

Degree

Master

Degree Date

2013

English Abstract

This study was carried out on two parts, the first part concerns fifty fasting male workers, age range 28-60 years exposed to mercury in a chloroalkali factory at Al-Furat company in Babylon Provience, range duration period 5-18 years and 25 controls matched for age, diet, and other demographic characteristics except exposure to chemicals were selected.

Lipid peroxidation marker malondialdehyde (MDA), antioxidant status markers enzymatic superoxide dismutase (SOD), glutathione peroxidase (GPx), non enzymatic antioxidant markers, glutathione (GSH), vitamin C, vitamin E and other biochemical indices including plasma lipid profile, liver and renal function tests and oxidative DNA damage by comet assay were determined.

Blood Mercury levels were significantly higher in the workers G3 and G2 groups compared with controls G1 (p<0.001).

MDA was also significantly increased and positively correlated with the concentration of Hg (r = 0.46, p<0.01), probably to match the body chemical burden, while levels of non enzymatic antioxidant GSH, vitamin C, E and enzymatic antioxidant SOD and GPx were in contrast significantly lower in both workers than in controls (p<0.01).

Liver transaminase activities serum aspartate aminotransferase (S.AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were significantly higher in both workers group G3&G2 than in controls (p<0.01).

Total cholesterol was significantly reduced in chemical workers (p<0.01) while triglyceride levels increased.

Other variables such as total serum bilirubin and urea did not differ significantly.

These data are consistent with the existence of oxidative stress in these chemical workers through the generation of free radicals and alteration of the cellular antioxidant defense system.

II The present study indicates that workers occupationally exposed to mercury, in the particular conditions of exposure of this collective evaluated, show clear evidence of genotoxic activity in their lymphocytes especially in group G3 than group G2 against healthy control group G1 and this genotoxic activity (DNA damage by comet assay) is correlated positively with the long period of exposure to mercury pollution.

DNA damage in mercury-exposed individuals suggests that mercury overload induces an imbalance in the redox cycle.

The part two of this study has been carried out to investigate the effect of inorganic mercury (HgCl2) exposure on biochemical parameters in adult male mice.

80 mice whose average body weight was about 25 g were included in the experiment and divided randomly into 4 groups each 20 mice for each.

The first group: served as control and the mice were injected with vehicles only (50μl of deionized water).

The second group: was injected subcutaneously with mercury chloride daily at a dose of 0.16 mg/kg body weight for 30 days.

The third group: was injected subcutaneously with mercury chloride daily at a dose of 0.32 mg/kg body weight for 30 days.

The four groups: was injected subcutaneously with mercury chloride daily at a dose of 0.48 mg/kg body weight for 30 days.

At the end of each treatment period, the corresponding group of animals (both control and intoxicated groups) was euthanized in order to measure all the parameter which measured in human study in addition to histological study.

The results revealed that the mice treated with HgCl2 (G4,G3,G2) showed a significant increase in MDA levels, S.AST, S.ALT, S.ALP, triglycerides and low density lipoprotein-cholesterol (LDL-C).

Moreover, GSH, vitamin C&E levels of HgCl2 group depleted significantly.

On the other hand, serum cholesterol, high density lipoprotein-cholesterol (HDL-C) and SOD, GPx of III HgCl2 treated animal group showed a significant decrease compared to the control group and these changes in all biomarkers were dose dependent of mercury administrated (G4>G3>G2).

Mercury intoxication induces some pathological alterations in the liver as necrosis and cytoplasmic vacuolization.

The rise in plasma hepatic enzymes, triglycerides, LDL-C, hydroperoxide, and histopathological changes were significantly depending on long period of exposure to mercury.

The oxidative DNA damage by alkaline comet assay method showed a significant increase in comet length in all three treatment mice groups as compared to controls .This data indicates that increasing concentration of HgCl2 is associated with the migration of damaged head DNA from head to the tail region during electrophoresis.

Our results suggest that mercury treatment is associated with oxidative stress leading to oxidative DNA damage.

Therefore, DNA damage in the peripheral blood could be a suitable early bio-marker to monitor the environmental or occupational mercury toxicity.

Main Subjects

Biology

No. of Pages

182

Table of Contents

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Language

English

Data Type

Arab Theses

Record ID

BIM-601156