The impact of enriched environments on cerebral oxidative balance in rodents: a systematic review of environmental variability effects

Introduction

The present review aimed to systematically summarize the impacts of environmental enrichment (EE) on cerebral oxidative balance in rodents exposed to normal and unfavorable environmental conditions.

Methods

In this systematic review, four databases were used: PubMed (830 articles), Scopus (126 articles), Embase (127 articles), and Science Direct (794 articles). Eligibility criteria were applied based on the Population, Intervention, Comparison, Outcomes, and Study (PICOS) strategy to reduce the risk of bias. The searches were carried out by two independent researchers; in case of disagreement, a third participant was requested. After the selection and inclusion of articles, data related to sample characteristics and the EE protocol (time of exposure to EE, number of animals, and size of the environment) were extracted, as well as data related to brain tissues and biomarkers of oxidative balance, including carbonyls, malondialdehyde, nitrotyrosine, oxygen-reactive species, and glutathione (reduced/oxidized).

Results

A total of 1,877 articles were found in the four databases, of which 16 studies were included in this systematic review. The results showed that different EE protocols were able to produce a global increase in antioxidant capacity, both enzymatic and non-enzymatic, which are the main factors for the neuroprotective effects in the central nervous system (CNS) subjected to unfavorable conditions. Furthermore, it was possible to notice a slowdown in neural dysfunction associated with oxidative damage, especially in the prefrontal structure in mice.

Discussion

In conclusion, EE protocols were determined to be valid tools for improving oxidative balance in the CNS. The global decrease in oxidative stress biomarkers indicates refinement in reactive oxygen species detoxification, triggering an improvement in the antioxidant network.

Interleukin-33 Expression on Treatment Outcomes and Prognosis in Brazilian Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy

Interleukin-33 (IL-33), a member of the interleukin-1(IL-1) family of cytokines, remains poorly understood in the context of human breast cancer and its impact on treatment outcomes. This study aimed to elucidate IL-33 expression patterns within tumor samples from a cohort of Brazilian female breast cancer patients undergoing neoadjuvant chemotherapy while exploring its correlation with clinicopathological markers. In total, 68 samples were meticulously evaluated, with IL-33 expression quantified through a quantitative polymerase chain reaction. The findings revealed a substantial upregulation of IL-33 expression in breast cancer patient samples, specifically within the Triple-negative and Luminal A and B subtypes, when compared to controls (healthy breast tissues). Notably, the Luminal B subtype displayed a marked elevation in IL-33 expression relative to the Luminal A subtype (p < 0.05). Moreover, a progressive surge in IL-33 expression was discerned among Luminal subtype patients with TNM 4 staging criteria, further underscoring its significance (p < 0.005). Furthermore, chemotherapy-naïve patients of Luminal A and B subtypes exhibited heightened IL-33 expression (p < 0.05). Collectively, our findings propose that chemotherapy could potentially mitigate tumor aggressiveness by suppressing IL-33 expression in breast cancer, thus warranting consideration as a prognostic marker for gauging chemotherapy response and predicting disease progression in Luminal subtype patients. This study not only sheds light on the intricate roles of IL-33 in breast cancer but also offers valuable insights for future IL-33-related research endeavors within this context.