| As the living standard improves, people have higher requirements for interior living environment than before and then the indoor decoration trend is gradually upward. Therefore, the indoor air pollution caused by volatile organic compounds of the decorative materials has become a significant public health problem. In the indoor volatile organic compounds, formaldehyde and benzene are the most-watched indoor air pollutants in particular with their high levels of pollution and great harm to people’s health. Many scholars at home and abroad have conducted a lot of research work on the separate immune toxicity of formaldehyde and benzene, whereas the research on the combined immunotoxic effects of formaldehyde and benzene and its related mechanisms is not much. Therefore, in this study the mice was exposed to the combined exposure of formaldehyde and benzene and then explore the combined toxic effect of formaldehyde and benzene on mice immune system and its related mechanisms from these aspects of immune molecules, immune cells, immune organs and immune responses.The animals were divided randomly into five exposure groups of 6 mice each as follows:(A) blank control group (Ctrl); (B) solvent(corn oil) control group (Oil), intragastrically administration with freshly prepared corn oil (5 mL/kg body weight, once daily for 5 days/week for 2 weeks); (C) benzene group (BZ), intragastrically administration with freshly prepared corn oil solutions of benzene (150 mg/kg body weight, once daily for 5 days/week for 2 weeks); (D) formaldehyde group (FA), mice were placed in a glass cylinder which was introuduced gaseous formaldehyde (3mg/m3, 8 hr/day,5 days/week for 2 weeks):(E) formaldehyde with benzene group (FA+BZ), mice were treated with the exposure way of formaldehyde group and benzene group. At the last day of exposure, we conducted the tail blood preoaration of mice after 8-hour exposure. Then all of the mice were sacrificed for sample preparation the next day and a series of physiological and biochemical indexes were measured and observated.The FA group and BZ group had no effect on the mice weight gain compared with the Ctrl group, but the FA+BZ group can lead to a apparent decrease on the trend of the mice weight gain; 2. The FA group had no effect on the amounts of white cell, lymphocyte, granulocyte and monocyte in the peripheral blood, but the BZ group and FA+BZ group can lead to a significant decrease of their amounts (p<0.05), and the amounts of white cell and lymphocyte in the the FA+BZ group mice’s peripheral blood have significantly reduced (p<0.05) compared with the BZ group; 3. The BZ group and FA+BZ group can lead to a significant decrease of spleen coefficient (p<0.05); 4. All three exposure groups can cause oxidative damage and DNA damage in varying degrees on nucleate cells of the bone marrow and spleen in mice, and the degrees of injuries caused by the combined exporsure of formaldehyde and benzene on some biochemical indexes are apparently larger than these of the exporsure of formaldehyde or benzene separately; 5. All three exposure groups can cause a increase with different degrees of the expression of activated Caspase-3 in spleen nucleate cells (p<0.05); 6. All three exposure groups can cause injuries of immune tissue in mouse spleen and the degree of the injury caused by the combined exporsure of formaldehyde and benzene is apparently larger than these of the exporsure of formaldehyde or benzene separately; 7. The FA+BZ group can significantly inhibit the proliferative ability of splenic T-cells in mice and mouse serum hemolysin titer.Both formaldehyde and benzene can cause the toxic effects with varying degrees on mice immune system, and the toxic effects caused by the joint action of formaldehyde and benzene have some synergy. The interactions between the oxidative damages and DNA damages of tissue cells in mice immune organs may be an important mechanism to make mice immune tissue impaired and result in the impairment of mice immune function. |
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