Efeitos de doses subletais de inseticidas biológicos, administrados durante prenhez e lactação, sobre aspectos reprodutivos, hepático e renal de filhotes de ratas Wistar

Abstract

Due to their large-scale use, insecticides are among the most important risk factors for the health of man, animals, and the environment. As an alternative to the use of chemical insecticides, bioinsecticides based on the Cry proteins of Bacillus thuringiensis are a significant and widely used strategy against insect pests. However, although these proteins are considered safe for vertebrates, studies have shown results that disagree with this statement. Therefore, this research aims to investigate the possible effects on reproductive, hepatic and renal morphophysiology in puppies of rats that received the biological insecticides XenTari® WG and Dipel® during pregnancy and lactation. Twenty rats, Rattus norvegicus albinus of the Wistar strain, 90 days old, mated and divided into the following groups were used: CG - Pregnant rats; GX - Pregnant rats that received XenTari® WG (B. thuringiensis subsp. Aizawai); GDi - Pregnant rats that received Dipel® (B. thuringiensis var. Kurstaki); and GDe - Pregnant rats that received deltamethrin (Keshet® 25EC). Insecticides were administered by gavage, at a dosage of 1mg/100g/day (Groups GX and GDi), and 2mg/Kg/day (Group GDe), throughout pregnancy and lactation. The results revealed that the administration of biological and synthetic insecticides reduced the weight gain of the matrices when compared to the control group. Biological insecticides also promoted a reduction in offspring, weight, and length, causing malformation and mortality. There was a delay in the vaginal opening period, an increase in the metestrus about the other phases, a reduction in estrogen, progesterone (females) and testosterone (males), ovaries with numerous tertiary follicles, atresia and few corpus luteum in the offspring of the three groups that received insecticides and, only in the XenTari® and Dipel® groups, histopathological changes in the testicles were observed, with vacuolations and desquamation of the seminiferous epithelium. Quantitative analysis of androgen and estrogen receptors revealed a significant reduction for both offspring gonads whose rats received biological insecticides and deltamethrin, and in these same groups, testicular morphometry revealed a reduction in tubular diameter, height of seminiferous epithelium and tubular total length, and in the ovaries there was a smaller number of primary, secondary and corpus luteum follicles, and an increase in the number of tertiary and atretic follicles. The administration of insecticides also reduced the levels of biomarkers of toxicity alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea and creatinine, and the biological insecticides promoted histopathological changes in the liver, with the presence of portal vein, centrilobular and sinusoid capillaries congestion, and in the kidney, presence of cortical congestion and reduction of the subcapsular space. There was a significant reduction in glycogen in the liver, and the morphometry revealed a reduction in the lobular parenchyma and an increase in the non-lobular parenchyma, while in the kidney there was a reduction in the diameter and volume of the glomerulus and Bowman's capsule in the offspring of the rats treated with the insecticides. Thus, it is concluded that both the biological insecticides XenTari® and Dipel®, as well as the synthetic insecticide deltamethrin, in sublethal doses in pregnant rats, promote reproductive, hepatic and renal changes, and in the development of the puppies, being which last until the adult phase, most of these effects were even more expressive in the groups that received biological insecticides.