Análise morfofuncional de testículos murinos tratados com antineoplásico 5 - fluorouracil: comparação qualitativa entre duas colorações histológicas

Abstract

Cancer is a multifactorial disease that affects the world’s population. Treatment strategies include antineoplastic drugs such as 5-Fluorouracil, which affect the metabolism of cancer cells and healthy cells with high proliferation rates, such as reproductive cells. In the male reproductive system, this drug causes morphological damages capable of reducing the production of viable spermatozoa, thus reducing the fertility of these individuals. Therefore, when evaluating tissues damaged by cytotoxic agents, histology typically uses Hematoxylin and Eosin (HE) staining as a traditional method, which can cause limitations in identifying damage to the cells that make up the seminiferous tissue. Hence, various tools can be implemented to increase the reliability of the reading, including Gomori's trichrome stain, which highlights the histopathological characteristics and yet there have been no studies using it for this purpose in tissue treated with chemotherapy drugs. The aim of this study is to evaluate the use of Gomori staining in the challenging histopathological analysis of murine testicular tissues treated with 5-FU, under the hypothesis that this method will lead to more assertive readings. Adult male Swiss mice were divided into two groups of administration: i. a single intraperitoneal dose of 450 mg/kg of 5-FU; ii. saline solution at 0,1ml/10g i.p. They were then euthanized for testicular evaluation, which were processed for classical histology, HE and TG staining. The TS were then evaluated on a scale of 0 to 3 for epithelial and cellular changes, where 0 means no modification and 1, 2, and 3 are increasing degrees of alteration. In addition, the observation of conjunctival alterations was evaluated by cross scores in which (-) means no alteration and (+), there was alteration. As expected, the control group remained preserved, and both stains were positively applicable for reading the intra and intertubular microenvironments. Among the results when investigating the conservation of the seminiferous epithelium in the 5- FU group, HE was efficient in cellular aspects, such as spermatogenic differentiation and in showing the disordered distribution of these cell populations. Alternatively, TG was able to highlight the changes following treatment with 5-FU, focusing on aspects such as cell debris, differentiation between late spermatids and spermatozoa and cytoplasmic enhancement of spermatogenic cells. Overall, no prominent structural changes were observed in the interstitial connective tissue of mice from both groups, due to the low frequency of collagen fibers found in the tissue. From this perspective, HE evaluations highlighted the interstitium with grouped Leydig cells and little amorphous connective tissue content. However, TG allowed a clear visualization of myoid cells around the seminiferous tubules, the discrete basal membrane delimitation found in murines and fibroblasts in smaller quantities in the interstitium. It is therefore concluded that although HE staining is practical and achievable, it is a method that has limitations in interpretation and can be improved. Thus, using TG for histopathological evaluations can be a more effective tool in describing tissue components for fundamental information on the toxicity of 5-FU.