The Effects Of Subchronic Low Level Arsenic Exposure On Blood System In Rabbit

Objective:To investigate the effects of subchronic low arsenic exposure on blood cell and vascular in rabbits.Methods:Twelve healthy male rabbits were randomly divided into four groups.They were administrated with NaAsO₂ at the concentration of 0μg/L,10μg/L,50μg/L and 250μg/L in the drinking water for 12 weeks.Body weights were measured at 0w,8w and 12w,and the photos of the optic fundi were captured at the same times with the body weights.Then the changes of the body weights and optic fundi vessel were observed.The blood samples for the anticoagulants and nonanticoagulants were collected at 8w and 12w.The blood cells(e.g.WBC,RBC,PLT et al) were detected by the hemocyte analyzer and the liver injury indexs(e.g.ALT,AST,GGT,ALP,TP and ALB) were detected by the automatic biochemistry analyzer.Then the rabbits were killed with the ethylcarbamate at 12w and the main organs were collected to observe the organ index.The morphological changes of the liver vascular were observed by light microscopy.The expression of VEGF in the liver was detected by immunohistochemical method.Results:1.Compared with the controls,the body weight has an increasing tendency at the three treatment groups,and the low group increases obviously,but there are not significant differences in body weight(P＞0.05).The lung index increases at middle dose(P＜0.05) and heart index increases at low and middle doses(P＜0.05).And the others do not change at all.2.Compared with the controls,WBC increase because of the increase of the GRA.LYM% decrease in middle and high dose at 8w and 12w,but there are no significant differences (P＞0.05).MPV decrease in middle dose significantly at 8w(P＜0.05),but do not change at 12w. The PLT decrease in high dose at 8w and decrease in low,middle and high doses at 12w,and there is significant(P＜0.05).The other indexs don't change at all.3.The framework of the controls' lobules of liver is complete,and there is no heaptocellular necrosis and infiltration of the inflammation cells by the light microscopy.There are expansions and congestions in central veins and hepatic sinusoid at the middle dose.At the high dose,there are not only the expansions and congestions of the vascular,but also the narrow of the hepatic cord.There are also the infiltration of the inflammation cells in header campus at high dose. There is no change in the retina vessels of the controls.There are expansions of the vessles at middle and high dose,and there are some hemorrhages in the retina at high dose.4.The expression of the VEGF is higher in the arsenic groups than the controls,and gets to the peak at middle dose,then decrease a little at high dose.5.At 8w and 12w,the AST decreases obviously at the three treatment groups,and there are significant differences in high dose(P＜0.05).The ALP increases significantly in the high dose at 12w(P＜0.05),and does not change at 8w.Compared with the controls,there are no changement in ALT,GGT,TP and ALB at 8w and 12w.Conclusions:1.Subchronic low level arsenic exposure may lead to the increase of the WBC and the decrease of the PLT in the blood system.And the increase of the WBC is due to the increase of the heterophil granulocytes.2.Subchronic low level arsenic exposure have not severe effects on liver function,but the vascular of the liver has a conspicuous expansion and congestion.It indicates that the early injury of the low arsenic exposure is mailly at the vessels.3.Subchronic low level arsenic exposure may lead to the expansion of the retina vessels and some hemorrhages in the retina at high dose.4.Arsenic may increase the expression of the VEGF at a definite extent,and to promote angiogenesis. The concrete mechanisms need to be the next studies.