The complex process of carcinogenesis can be modulated by the action of environmental endocrine disruptors, such as the organophosphate pesticide Dichlorvos (DDVP), capable of interfering in homeostasis of different organs and leading to the development of neoplastic lesions. Considering that prostate cancer is the second most common neoplasm in men, worldwide, it is emphasized the importance of studying morphological alterations using animal models. In rodents, tumor initiation can be induced by the carcinogen N‐methyl‐N‐nitrosourea (MNU) and tumor promotion can be stimulated by the administration of testosterone, combinated or not with the use of pesticides. The present study aimed to evaluate the influence of DDVP on the development of morphological alterations in the ventral prostate of rats, after chemical induction by MNU. Thereunto, 32 Fischer 344 rats, aged 90 days, were randomly separated into four experimental groups: Control, DDVP, MNU, MNU+DDVP. For chemical induction, the MNU and MNU+DDVP groups were inoculated with MNU (15 mg/kg), followed by daily subcutaneous injections of testosterone cypionate (2.5 mg/kg), for 20 days. Animals of the DDVP and MNU+DDVP groups, from 120 to 240 days old, received the basal diet supplemented with 10 mg/kg of DDVP. Subsequent to the experimental period, the prostatic ventral lobe of each animal was collected and subjected to morphometric‐stereological and histopathological analysis, for the classification of the lesions found. The incidence of alterations in epithelium and stroma of all experimental groups was evaluated, such as epithelial hyperplasia (increased cell population with stratification, without atypia) (Figure A and B); atrophy (retraction of the epithelium with reduction of the secretory cytoplasm) (Figure C and D); periacinary inflammatory foci (presence of inflammatory cell infiltrate) (Figure E and F); cell atypia with presence of cytoplasmic inclusions (Figure G and H) and metaplasia with stromal hyperplasia (change in the pattern of the original epithelium without proliferative change, with an increase in the adjacent stroma) (Figure I to L). The results showed a significant increase of epithelial hyperplasia areas in MNU and MNU+DDVP groups, with 100% of the animals showing this lesion (Table 1), which demonstrates a relation between chemical induction and the proliferative process. The morphometric‐stereological analysis confirmed this finding, revealing a relatively greater volume of the epithelial compartment in MNU+DDVP, compared to the Control group (Table 2). Thus, it can be concluded that DDVP, even in low concentration, associated with chemical induction by MNU, was able to disturb the morphology of the ventral prostate, promoting proliferative epithelial lesions, strongly associated with the process of carcinogenesis.

Organophosphorus pesticides, such as dichlorvos (DDVP), are widely used in agricultural, commercial, industrial and domestic areas, even though there are many studies that prove their action as endocrine disruptors. They are able to interfere with homeostasis maintained by hormones, disrupting the hypothalamic‐pituitary‐testicular axis and inducing inflammation.Inflammation stimulates carcinogenesis, causing damage to cells and the genome, promoting cell replacement and creating a tissue microenvironment rich in cytokines and growth factors that may increase cell replication, angiogenesis, and repair tissue. The inflammatory process predisposes individuals to various types of cancer, as it induces the production of cytokines such as Tumor necrosis factor alpha (TNFα) which is involved in the development of prostate cancer. Inflammation can be triggered by Toll‐Like receptors (TLRs) which may result in the activation of, for example, Nuclear factor kappa B (NFκB), which plays an important role in cancer responses, inflammation, stress and cell differentiation.Thus, the objective of this work was to evaluate the immunolocalization of inflammatory mediators such as TNFα, TLR4 and NFκB in the ventral prostate of rats after exposure to DDVP, associated or not with chemical induction by N‐methyl‐N‐nitrosourea (MNU).A total of 40 rats of the Fischer 344 strain were used, at the age of 90 days. Rats were randomly assigned to four experimental groups: Sham (G1), Sham + DDVP (G2), MNU (G3), MNU + DDVP (G4). For chemical induction, G3 and G4 were inoculated with MNU at 15 mg / kg, followed by daily subcutaneous injections of 2.5 mg / kg of testosterone cypionate for 20 days. Animals of the G2 and G4 groups, from 120 to 240 days old, received the basal diet supplemented with 10 mg / kg of DDVP. Immunohistochemical analysis of the ventral prostate were performed.TNFα was detected in the whole cytoplasm of luminal epithelial cells in the ventral prostate of all experimental groups, with intense immunoreactivity in the apical region and moderate immunoreactivity in the region of the Golgi apparatus of these cells. The G1 group showed TNFα nuclear localization (fig. 1).The presence of TLR4 in luminal epithelial cells was detected. In groups G1, G2 and G3 there was immunolabeling in the whole cytoplasm of the cells, being the most intense expression in the Golgi apparatus region. In the G4 group, there was immunolabeling in the whole cytoplasm as well, but with moderate intensity in the Golgi apparatus and intense in the apical membrane of the cells (fig. 2).In all experimental groups, NFkB was immunolocalized in the whole cytoplasm of luminal epithelial cells in the ventral prostate. In addition, the G1 and G2 groups showed intense immunoreactivity in the apical region and only the G3 and G4 groups showed immunoreactivity in the perinuclear region and in the nuclear envelope (fig. 3).Thus, we can conclude that exposure to DDVP may alter the immunolocalization pattern of inflammatory mediators, such as NFκB, TNFα and TLR4. And, when associated DDVP with chemical induction by MNU, these changes are accentuated.Support or Funding InformationFAPESP 2017/08505‐5This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Organophosphorus pesticides are very effective, widely used, and pose a great risk to the environment and the health of various organisms, including humans. Dichlorvos (DDVP) is one of these pesticides and it has a mutagenic and carcinogenic potential for humans. Many pesticides, such as DDVP, act as endocrine disrupters and can alter endocrine homeostasis. These compounds act via androgen receptors (AR) or via estrogen receptors (ERs), promoting endocrine and reproductive changes, such as prostate cancer. Both androgens and estrogens are closely linked to the control of proliferation and cell death mechanisms that control normal prostate growth. Changes in the expression and activity of ARs and ERs are essential for understanding the process of carcinogenesis in the prostate.The present project aims to evaluate the expression of the AR, ERα and ERβ receptors in the ventral prostate of rats after exposure to the pesticide Dichlorvos, associated or not to chemical induction by MNU.A total of 40 rats of the Fischer 344 strain, at the age of 90 days, were used. Rats were randomly assigned to four experimental groups: Sham (G1), Sham + DDVP (G2), MNU (G3), MNU + DDVP (G4). For chemical induction, G3 and G4 were inoculated with MNU at 15 mg/kg, followed by daily subcutaneous injections of 2.5 mg/kg of testosterone cypionate for 20 days. Animals of the G2 and G4 groups, from 120 to 240 days old, received the basal diet supplemented with 10 mg/kg of DDVP. Western Blotting analysis of the ventral prostate was performed for AR (fig. 1), ERα (fig. 2) and ERβ (fig. 3) with β‐actin (fig. 4) loading control.In the densitometric analysis, it was verified that the expression of AR is higher in the G2 group than in the G1. When comparing the G3 group to the G1 group, it is noted that the expression of AR is higher in the G3 group. Thus, it is possible to infer that the expression of AR increases, both after exposure to DDVP and after chemical induction by MNU (fig. 5).In the densitometric analysis, it was also verified that ERα expression is higher in the G2 group than in the G1 group. When comparing the G3 group to the G1 group, it is noted that the ERα expression is higher in the G3 group. It is also observed that the ERα expression is higher in the G4 group than in the G2 group. The G4 group, on the other hand, presents ERα expression equal to that of G3. Thus, it is possible to infer that ERα expression increases, both after exposure to DDVP and after chemical induction by MNU (fig. 6).It has also been shown that ERβ expression is lower in the G2 group than in the G1 group. When comparing the G3 group to the G1 group, it is noted that the ERβ expression is lower in the G3 group. It is also observed that the ERβ expression is lower in the G4 group than in the G2 group. The G4 group, on the other hand, has lower ERβ expression than G3. Thus, it is possible to infer that ERβ expression decreases, both after exposure to DDVP and after chemical induction by MNU (fig. 7).Thus, we can conclude that the exposure to the pesticide DDVP alters the expression of hormone receptors in the ventral prostate of rats and can act as an endocrine disruptor.Support or Funding InformationFapesp 2014/07329‐0This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.