Blood coagulation system in chronic benzene poisoning via inhalation

Abstract

Aim. To experimentally study the changes occurring in blood coagulation system in exposure to low-dose benzene. 
 Methods. The experiment was performed on 36 rabbits by chronic exposure of the animals to benzene during 4 months on a daily basis 4 hours a day with 1 non-exposure day a week and a one-month recovery period after the end of exposure. The average poisoning concentration of benzene in the chambers was between 1240±82 mg/m3. The animals were divided into three groups: group 1 was exposed to gradually increasing concentration of benzene, group 2 - to fluctuating (intermittent) concentrations of benzene, group 3 included unexposed to benzene animals and was used as the control group. Overall blood clotting activity, blood clotting time, blood clot retraction, plasma recalcification time, plasma tolerance to heparin, prothrombin index, fibrinogen concentration, blood fibrinolytic activity were determined. 
 Results. In a month after exposure blood clot retraction rates in groups 1 and 2 increased by 79.8 and 23.1% respectively. Plasma tolerance to heparin most significantly changed in animals from group 2 (by 15.4%). Prothrombin time increased by 11.4% in group 1 while in group 3 this parameter decreased by 0.4%. Prothrombin index in group 1 decreased by 4.3%, and in group 2 the changes were not statistically significant. Concentration of fibrinogen in the blood in group 1 had no significant changes and decreased by 4.2% while in group 2 it decreased by 10.4%. Fibrinolytic activity in group 1 and 2 decreased by 47.5 and 5.8% respectively. 
 Conclusion. The studied benzene concentrations impair blood coagulation and anti-coagulation systems including two stages of hemostasis: 1st stage - from factor XII activation, 2nd stage - from prothrombin (factor II) activation.