ABSTRACT Purpose: To investigate the effect of chronic stress on testicular morphology in adult Wistar rats, as well as the impact of comfort food consumption on these parameters. Material and methods: 32 Wistar rats (10 weeks old) were divided into four groups: control (C), stressed (S), control + comfort food (C+CF), and stressed + comfort food (S+CF). Chronic stress was induced by the restraint method during 8 weeks in groups S and S+CF, while groups C and C+CF were maintained under normal conditions. Groups C and S received a standard rat chow diet, while groups C+CF and S+CF received both the standard chow and comfort food (Froot Loops®). After 8 weeks of experiment, all animals were euthanized and the testes were collected for histomorphometric, immunohistochemical and gene expression analysis. Results: Comfort food was preferred over standard chow in groups C+CF and S+CF, but this preference was more preeminent in stressed animals (S+CF). The consumption of comfort food resulted in testicular weight reduction. The seminipherous epithelium was reduced in group S in comparison to controls. While comfort food also reduced the epithelium in C+CF in comparison to controls, for group S+CF the comfort food ameliorated the stress-induced damage. The cell proliferation rate and the relative expression of StAR and BLC2 genes were similar between the groups. Conclusion: Both chronic stress and comfort food consumption resulted in morphological alterations of the testes but the consumption of comfort foods during chronic stress partially prevented the stress-induced detrimental effects on testes.

RESUMO Objetivo: O propósito deste estudo foi reproduzir em camundongos um modelo de sarcomas ósseos para uso em pesquisa oncológica. Método: Amostras frescas de tecido tumoral foram implantadas por via subcutânea em camundongos Nude. Quando o xenoenxerto derivado do paciente (PDX) alcançava 1500 mm3, ele era retirado do animal e reimplantado em outros camundongos. Estudos histológicos foram realizados para comparar as características morfológicas de diferentes gerações de xenoenxertos com o tumor primário. Resultados: Dezesseis amostras de tecido sarcomatoso foram enxertadas em camundongos. Nove pacientes foram diagnosticados com osteossarcoma, dois com condrossarcoma, dois com tumor maligno de bainha de nervo periférico, um com sarcoma sinovial, um com sarcoma pleomórfico e um com sarcoma de Ewing. Foram gerados tumores PDX em 11 das 16 amostras enxertadas (taxa de sucesso de 69% em P1). Destes, seis tumores P1 cresceram o suficiente para serem transferidos para outros camundongos, dando origem à geração P2 e três dos tumores P2 estabeleceram a geração P3. Conclusões: Os tumores PDX de sarcomas ósseos foram estabelecidos com sucesso em camundongos imunodeficientes e reproduziram com alta precisão as características do tumor primário. O modelo pré-clínico de PDX descrito pode representar uma ferramenta importante para a pesquisa oncológica translacional e para avaliar estratégias terapêuticas para sarcomas ósseos. Nível de Evidência I; Estudo experimental.

ABSTRACT Objective: The purpose of this study was to reproduce a mouse model of bone sarcomas for use in cancer research. Methods: A fresh sample of the tumor tissue was implanted subcutaneously into nude mice. When the patient-derived xenograft (PDX) reached a volume of 1500 mm3, it was harvested for re-implantation into additional mice. Histology was used to compare the morphological characteristics of different generations of sarcoma xenografts with the primary tumor. Results: Sixteen sarcoma tissue samples were engrafted into nude mice. Nine patients were diagnosed with osteosarcoma, two with chondrosarcoma, two with malignant peripheral nerve sheath tumor, one with synovial sarcoma, one with pleomorphic sarcoma, and one with Ewing’s sarcoma. PDX tumors were generated in 11 of the 16 implanted specimens (69% success rate in P1). Six P1 tumors grew sufficiently for transfer into additional mice, producing the P2 generation, and three P2 tumors established the P3 generation. Conclusion: PDX tumors generated from bone sarcomas were successfully established in immunodeficient mice and reproduced the characteristics of the primary tumor with a high degree of fidelity. The preclinical PDX model described herein may represent an important tool for translational oncology research and for evaluating therapeutic strategies for bone sarcomas. Level of Evidence I; Experimental study.