Maksoud A. H. A, Mahfouz M. K, Omnia M. A, Abdullah M. H, Eltabey M. E, Elharrif M. G. Biochemical Changes Followed Experimental Respiratory Distress by Benzene Vapours. Biomed Pharmacol J 2019;12(1).

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Manuscript received on :9-Oct-2018
Manuscript accepted on :24-Nov-2018
Published online on: 05-03-2019

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Plagiarism Check: Yes
Reviewed by: Sadegh Rajabi
Second Review by: Shaimaa Mutlak
Final Approval by: Dr. Ian James Martin

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Abdel Maksoud H. A¹, Mahfouz M. K¹, Omnia M. A¹, Abdullah M. H², Eltabey M. E¹ and Mohamed G. Elharrif³

¹Department of Biochemisry, Benha University, Egypt.

²Department of Biochemisry, 6^th October University, Egypt.

³Department of Basic Medical Sciences, Shaqra university, KSA, Kingdom of Saudi Arabia.

Corresponding Author E-mail: al_harrif@yahoo.com

DOI : https://dx.doi.org/10.13005/bpj/1654

Abstract

Monitoring of exposure to chemical matters is seriously needed  for evaluating health hazards resulted from its inhalation. The present study was carried out to determine the biochemical, immunological and oxidative stress parameters as well as the possible histological effects of exposure to benzene vapours in male albino rats. Results indicated that; Benzene vapours exposure  induced significant increasing in Myeloperoxidase (MPO) enzyme levels. This goes with marked immunologic changes presented by decreases in immunoglobulins; IgA and IgG, along with increases in levels of IgM and IgE. Also, Malondialdehyde (MDA) levels were significantly increased. Meanwhile, reduction in different biochemical parameters including; Superoxide Dismutase  (SOD), Catalase (CAT) levels and Glutathione (GSH) content. Lung sections taken showed; Thickening of alveolar septa with chronic inflammation and /or fibrosis, Congested vessels/thick walled vessels and Peri-bronchiolar fibrosis. Hence, the study concluded that; prolonged benzene (BNZ) vapours exposure lead to biochemical, immune disterbance and histopathological changes  probably through potentiating oxidative stress and inflammation pathways.

Keywords

Benzene Exposure; Inflammatory Pathways; Oxidative Stress

Introduction

Benzene is an aromatic hydrocarbon; toxic to the blood forming organs. The severity of the damage depends on the level, timing and pattern of exposure. This volatile compound in urban air pollution induces DNA oxidation (Uzma et al., 2010). Chronic benzene vapours exposure leads to decrease in antioxidant enzymes activity and hematologic disorders. Oxidative stress produces reactive oxygen species (ROS) in excess of the available antioxidant buffering capacity (Adly., 2010). Moreover, iron and other transition metals leaching from particles or by their presence on particle surfaces play a role in the generation of ROS in biological systems (Ghio et al., 2000).

Metals and other inorganic elements play important roles in a wide variety of biological processes of living systems. Several essential transition elements, such as zinc, magnesium, iron, copper, cobalt and manganese participate in the control of various metabolic and signaling pathways. However, their rich coordination chemistry and redox properties are such that they are capable of escaping out of the control mechanisms, such as homeostasis, transport, compartmentalization, and binding to the designated tissue and cell constituents. Breakdown of these mechanisms, caused by stimuli such as benzene exposure has been involved in a large variety of diseases (Jomova and Valko, 2011). Disruption of metal homeostasis is known to modulate gene expression by interfering with signal transduction pathways. This action may lead to uncontrolled metal-mediated formation of free radicals participating in the modification of DNA bases, enhanced lipid peroxidation and altered sulfhydryl homeostasis (Valko et al., 2007).

Repeated exposure to kerosene and petrol fumes causes degenerative changes in the ultra structural integrity of the hepatic cells which may impair the normal liver functions  (Uboh et al., 2005).

Materials and Methods

Forty male albino rats, 12 weeks old were taken, and divided into three main groups; the first kept as a negative control group (Un-exposed), the second consisted of 15 rats subjected to benzene  vapors for 8 hours daily for 3 months and the third contained also 15 rats exposed to benzene vapours for 8 hours daily for 6 months. All rats were sacrificed and their lungs were immediately collected for analysis and placed in formalin solution 10.0 % to reserve organ cells for histopathological examination. All animal experiments were approved by the egyptian research institute.

Data Collection and Estimated Parameters

After 90 days of exposure to benzene vapours, blood samples will be collected from rats of each group. The samples will be taken in the early morning after overnight fasting from the medial conthus of the eyes by using the heparinized microhematocrite tubes to heparin and plain centrifuge tubes, then animals sacrificed. Plain tubes then allowed to be coagulate at room temperature for 30 minutes. The serum will be separated in dry sterile tube then kept in deep freeze until using for subsequent biochemical assays.

The sera were subjected to estimation of copper, zinc, iron, manganese, and lead by atomic absorption spectra-photometry (Pye Unicum), according the methods, described by Wilse, (1960) and Bauer (1982) as well as total protein immunoglobulines (IgM, IgG, IgA) (Whicker et al., 1984), IgE (Plebani et al., 1998) and nitric oxide. (Montgomery and Dymock, 1961) as well as Myeloperoxidse Enzyme activity (ELISA kit -Kamiya Biomedical Co.).

The remaining amount of blood were taken into clean dry tube containing heparin 0.5% and used for preparation of hemolysate by Digitonine after washing erythrocytes by physiological saline as described by Korrnburg and Korecker (1955). This hemolysate was subjected for quantitative determination of erythrocyte (CAT) (Aebi, 1984) and (Fossati et al., 1980), (SOD) (Nishikimi et al., 1972),, (GSH) (Beutler et al., 1963),(GP_X) (Paglia and Valentine, 1967)  and (MDA) (Satoh, 1978).

Statistical Analysis

Data analysis was expressed as mean ± S.E. and analyzed for statistical significance by one-way ANOVA followed by Tukey’s post-hoc test for multiple comparisons, using SPSS program for Windows version 22.0 (SPSS Inc., Chicago, USA). Values were considered statistically significant at P<0.05 correlations between the measured variables were assessed by linear regression analysis by the least squares method.

Results

Results obtained in table (1) showed a significant decrease (P<0.05) in serum Copper, Zinc and iron levels in rats exposed to benzene vapours for three months and highly significant decrease (P<0.05) in Cu, Zn after six months of exposure when compared to control. Also, a highly significant decrease was noticed in serum immunoglobulines IgG and IgA levels at (P<0.05) in spite of increasing of serum lead and cadmium metals, IgM and IgE in rats exposed to benzene vapours for three months and highly significant increase after six months of exposure when compared to control. Moreover, serum Nitric Oxide showed a significant decrease at (P<0.05) in rats exposed to benzene vapours for three months and highly significant decrease after six months of exposure in comparison with control. Serum MPO levels showed a significant increasing in rats exposed to benzene vapours for three months and highly significant increasing (P<0.05) after six months of exposure when compared to control.

The data recorded in table (2) showed; a significant reductions in RBCs SOD, CAT, GPx and GSH levels (P<0.05) in rats exposed to benzene vapours for three months and highly significant reduction in RBCs SOD, CAT, GPx and GSH levels after six months of exposure when compared to control. in spite of increasing of Lipid peroxidation, MDA levels in rats exposed to benzene vapours for three months and highly significant increase after six months of exposure when compared to control.

Table 1: Biochemical effect of benzene vapor on some serum biochemical parameters in male rats after 3 and 6 months of exposure.

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