Avaliação do efeito da exposição crônica ao Paraquat sobre a perda óssea alveolar. estudo in vivo

Abstract

Periodontal disease (PD) is a chronic inflammation that affects the tissues of coating and support of the teeth, induced by the presence of a dental biofilm. The host’s immune response a determinant factor for the progression of this disease and the production of reactive oxygen species (ROS) is an important mechanism causing tissue damages. Currently, this is the main cause of tooth loss in individuals over 40 years of age and affects approximately 538 million of people worldwide. This pathogenesis is influenced by several endogenous and exogenous factors in the host’s life, and living in rural area can be considered a risk factor for this disease. Residents of the rural areas have significant exposure to pesticides used in agriculture. Currently, much has been studied about the exposure effects of pesticides on human health, and is known that exposure to determined pesticides may represent a risk factor, including for PD. Paraquat, herbicide widely used in agriculture, also has its main mechanism of action based on liberation of ROS, which lead to lipid peroxidation and oxidative stress, causing tissue damage. Therefore, is suggested that the Paraquat may have influence about the high prevalence of PD in individuals residents in rural areas. Thus, the present study had as main objective evaluate the effects of Paraquat chronic exposure on alveolar bone loss (POA) induced by ligature method in rats. For this, a total of 40 rats were divided into four groups: Without Ligature / Without Paraquat Group (SL / SP); Group With Ligature / Without Paraquat (CL / SP); Without Ligature / With Paraquat Group (SL / CP); and Group With Ligature / With Paraquat (CL / CP). POA induction was realized by ligature method during 30 days and Paraquat exposure via intragastric gavage with dose of 0,1 mg/Kg during 60 days. The data obtained were analyzed using GraphPad Prism 6.0 software, using the two-way ANOVA statistical test and accepting significance level of 5%. Was evaluated the POA through the macroscopic analysis, the levels total of the leukocytes in the blood, the levels of the serum reduced glutathione and clinical parameters, what were dental mobility, gingival edema and gingival bleeding in these animals. On results obtained can be indicate that the Paraquat had a significant influence on the increase of the leucocytes and of the clinical signs evaluated, but only showed a tendency to decrease the levels of reduced glutathione and to increase the POA in the rats that had induction with ligature. Wherefore, this study concluded that Paraquat at dose of 0.1 mg / kg was not able to increase POA and neither decrease the levels of serum reduced glutathione in these animals significantly, but increase the levels of the leukocytes in the blood and the clinical signs of PD.