Browsing by Author "Silva, Jessica"
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- Aloysia citrodora extract as a chemopreventive agent against HPV16-induced lesions: findings from K14-HPV16 micePublication . Medeiros-Fonseca, Beatriz; Faustino-Rocha, Ana; Silva, Jessica; Silva, Mónica; Pires, Maria João; Neuparth, Maria João; Vala, Helena; Vasconcelos-Nóbrega, Cármen; Dias, Maria Inês; Barros, Lillian; Gonçalves, Lio; Gaivão, Isabel; Bastos, Margarida M.S.M.; Félix, Luís; Venâncio, Carlos; Medeiros, Rui; Costa, Rui Miguel Gil; Oliveira, Paula A.Aloysia citrodora has a long history of traditional use in treating various ailments. This study evaluated the in vivo chemopreventive efficacy and systemic toxicity of an extract of A. citrodora in a transgenic mouse model of HPV16 (human papillomavirus type 16)-induced cancer. Methods: The experiment involved six groups (n = 5): group 1 (G1, wild-type (WT), water), group 2 (G2, HPV, water), group 3 (G3, WT, 0.013 g/mL), group 4 (G4, HPV, 0.006 g/mL), group 5 (G5, HPV, 0.008 g/mL), and group 6 (G6, HPV, 0.013 g/mL). Throughout the assay, humane endpoints, body weight, food, and water consumption were recorded weekly. The internal organs and skin of the mice were collected for analysis after they were sacrificed. Toxicological parameters that were studied included hematological and biochemical blood markers, splenic and hepatic histology, and hepatic oxidative stress. Results: A. citrodora extract seems to reduce the incidence of dysplastic and in situ carcinoma skin lesions induced by HPV16 in this model, suggesting that dietary supplementation with concentrations of 0.008 g/mL and 0.013 g/mL may have beneficial chemopreventive effects. Conclusions: The extract did not induce any concentration-dependent toxicological effects on any of the parameters included in the study, indicating a favorable toxicological profile under these experimental conditions.
- Effects of Ladder-Climbing Exercise on Mammary Cancer: Data from a Chemically Induced Rat ModelPublication . Silva, Jessica; Azevedo, Tiago; Aires, Inês; Medeiros, Catarina; Neuparth, Maria J.; Seixas, Fernanda; Ferreira, Rita; Faustino-Rocha, Ana I.; Oliveira, Paula A.; Duarte, José AlbertoBreast cancer remains a significant global health issue, affecting both humans and companion animals, particularly female dogs and cats, where mammary tumors are among the most common cancers. Strategies to minimize the impact of this disease on patients, pet owners, and veterinary medicine are essential. This study analyses the effects of resistance training on the development of chemically induced mammary cancer in female Wistar rats, divided into four groups: sedentary control (CTR), sedentary induced (CTR+N-methyl-N-nitrosourea (MNU)), exercised control (EX), and exercised induced (EX+MNU). The exercise protocol involved ladder climbing three times a week for 18 weeks with the load progressively increasing. At the study’s end, blood and histopathological samples were collected and analyzed. Although tumor onset occurred two weeks earlier and incidence was slightly higher in the exercised group (EX+MNU) compared to the control group (CTR+MNU), the mortality rate was lower, and the malignancy was not as aggressive. No systemic inflammation was observed, as the levels of albumin, C-reactive protein (CRP), and interleukin 6 (IL-6) in the MNU groups remained similar to the controls. Exercise has been shown to promote overall health by increasing physical fitness, boosting immunological function, and improving metabolic health. These findings may offer valuable insights into the potential role of resistance training in managing mammary cancer in companion animals. However, further research is required to assess clinical applicability and to establish safe and effective exercise protocols for veterinary oncology.
- The Impact of a Western Diet and Resistance Training in a Rat Model of Mammary CancerPublication . Silva, Jessica; Ferreira, Rita; Neuparth, Maria J.; Seixas, Fernanda; Ginja, Mário; Pires, Maria J.; Faustino-Rocha, Ana I.; Duarte, José Alberto; Oliveira, Paula A.This study aimed to investigate the impact of a Western diet and resistance training on cardiac remodeling in a rat model of chemically induced mammary cancer. Fifty-six female Wistar rats were randomly assigned to one of eight experimental groups, evaluating the impact of Western and standard diets, exercise and sedentarism, and the induction of mammary cancer. Mammary cancer was induced via the intraperitoneal administration of N-methyl-N-nitrosourea (MNU) (50 mg/kg) at seven weeks of age. The resistance training protocol consisted of ladder climbing three times per week for an 18-week period, with a gradual increase in load over time. At the end of the 20-week experimental period, the animals were anesthetized and underwent echocardiography. Subsequently, the animals were euthanized, and organs and visceral adipose tissue (VAT) were collected and analyzed. A histopathological examination was performed on the mammary tumors. The Western diet increased relative VAT and contributed to cardiovascular and tumor-related changes, including an increase in interventricular septum thickness (IVS) and left ventricle posterior wall thickness (LVPW) at end-systole. Exercise reduced fat accumulation, improved cardiac performance, and helped regulate cardiovascular function, as indicated by a higher eccentricity index (EI) in the WD+EX group compared to the WD group. The WD was associated with increased VAT accumulation and initially delayed tumor initiation; however, over time, it contributed to bigger tumor aggressiveness. This diet also delayed tumor initiation but increased LVPW. Exercise, when combined with a WD, accelerated tumorigenesis, malignant transformation and invasiveness, resulted in the higher prevalence of invasive tumors. These findings underscore the complex and potentially compounding effects of diet and exercise on cancer progression.
- Interplay Between Western Diet and Mammary Cancer: Data from a Chemically-induced Model in Wistar RatsPublication . Silva, Jessica; Aires, Inês; Peixoto, Francisco P.; Neuparth, Maria João; Queiroga, Felisbina; Seixas, Fernanda; Ferreira, Rita; Faustino-Rocha, Ana; Duarte, José Alberto; Oliveira, Paula A.This study aimed to investigate the influence of Western diet on mammary cancer in Wistar female rats, focusing on systemic responses and tumor development. Materials and Methods: Twenty-eight Wistar female rats were acclimatized and divided into four experimental groups (n=7 each): Western diet (WD), Western diet with N-methyl-N-nitrosourea (MNU) administration (WD+MNU), standard diet (CTR), and standard diet with MNU administration (CTR+MNU). MNU was administered intraperitoneally at 50 mg/kg at seven weeks of age to induce mammary cancer. The 20-week experiment involved monitoring animal weight, food and water intake. At the end of the study, rats were euthanized, and blood samples and organs were collected for hematological and plasma biochemical analysis, oxidative stress, and histo-pathological and immunobiological evaluations of the tumors. Results: No significant differences were found in body weight, composition, or organ weights, but the WD group showed reduced food and water intake and lower cholesterol levels. Leptin and adiponectin levels were higher in the WD+MNU group, suggestive of changes in appetite regulation. Histopathological analysis showed malignant tumors in both MNU-induced groups. However, WD groups had fewer tumors compared to the CTR+MNU group. Conclusion: WD led to higher feed efficiency and increased visceral adipose tissue but decreased systemic cholesterol and triglyceride levels. While this diet resulted in lower tumor incidence, the volume and weight of the tumors were higher. Additionally, the WD decreased ERα and progesterone receptor immunoexpression, while Ki-67 immunoexpression was elevated.
- Realistic Aspects of Cardiac Ultrasound in Rats: Practical Tips for Improved ExaminationPublication . Silva, Jessica; Ginja, Mário; Oliveira, Paula A.; Duarte, José Alberto; Faustino-Rocha, AnaEchocardiography is a reliable and non-invasive method for assessing cardiac structure and function in both clinical and experimental settings, offering valuable insights into disease progression and treatment efficacy. The successful application of echocardiography in murine models of disease has enabled the evaluation of disease severity, drug testing, and continuous monitoring of cardiac function in these animals. However, there is insufficient standardization of echocardiographic measurements for smaller animals. This article aims to address this gap by providing a guide and practical tips for the appropriate acquisition and analysis of echocardiographic parameters in adult rats, which may also be applicable in other small rodents used for scientific purposes, like mice. With advancements in technology, such as ultrahigh-frequency ultrasonic transducers, echocardiography has become a highly sophisticated imaging modality, offering high temporal and spatial resolution imaging, thereby allowing for real-time monitoring of cardiac function throughout the lifespan of small animals. Moreover, it allows the assessment of cardiac complications associated with aging, cancer, diabetes, and obesity, as well as the monitoring of cardiotoxicity induced by therapeutic interventions in preclinical models, providing important information for translational research. Finally, this paper discusses the future directions of cardiac preclinical ultrasound, highlighting the need for continued standardization to advance research and improve clinical outcomes to facilitate early disease detection and the translation of findings into clinical practice.
- The role of natural compounds in rat mammary cancer: the beneficial effects of Santolina chamaecyparissus L. aqueous extractPublication . Azevedo, Tiago; Silva, Jessica; Peixoto, Francisco P.; Silvestre-Ferreira, Ana C.; Gama, Adelina; Seixas, Fernanda; Finimundy, Tiane C.; Barros, Lillian; Matos, Manuela; Oliveira, Paula A.; Faustino-Rocha, Ana; Valada, Abigaël; Anjos, Lara; Moura, Tânia; Ferreira, Rafaela; Santos, Marlene; Pires, Maria João; Neuparth, Maria JoãoBreast cancer is the most diagnosed cancer among women, and a leading cause of death worldwide. Santolina chamaecyparissus L. is a plant with multiple health benefits, including anticancer and anti-diabetic properties. This study aimed to assess the chemopreventive effects of S. chamaecyparissus aqueous extract (SCE) in an animal model of mammary cancer. A total of 28 four-week-old female Wistar rats were divided into four groups: control, MNU-induced (IND), SCE-supplemented (SCE), and SCE+IND. SCE was added to drinking water (12.72 mg/kg body weight) ad libitum. MNU was administered via the intraperitoneal route at 50 days of age. Weekly monitoring of body weight, food/drink intake, humane endpoints, and number of mammary tumours were recorded. Twenty weeks after MNU administration, animals were sacrificed by anaesthetic overdose and a necropsy was performed. Blood samples were used to determine blood count and serum biochemistry analysis, while kidney and liver samples were analysed for oxidative stress. Tumour samples were collected for gene expression and histology studies. SCE chemical composition was analysed by LC-MS and contained 19 phenolic compounds, with the most abundant being myricetin-O-glucuronide and 1,3-O-dicaffeoylquinic acid. Two animals in the IND group were sacrificed due to exceeding the humane endpoint limits. SCE supplementation delayed mammary tumour development, reducing its volume and weight. SCE had a positive impact on haematological parameters, particularly the neutrophil-lymphocyte ratio (P=0.026). No significant differences were observed in serum biochemistry, except for creatinine kinase MB, or in oxidative stress markers. Gene expression analysis showed significantly reduced VEGF expression levels (P=0.0158) in tumours from SCE+IND. These findings suggest that SCE is deserving of further study to identify the individual compounds and to understand its influence on animal models during cancer development.