RESUMO
The Brazilian National Network of Alternative Methods (RENAMA), which is linked to the Ministry of Science, Technology and Innovation, is currently comprised of 51 laboratories from CROs, academia, industry and government. RENAMA's aim is to develop and validate new approach methodologies (NAMs), as well as train researchers and disseminate information on their use - thus reducing Brazilian, and consequently Latin American, dependence on external technology. Moreover, it promotes the adoption of NAMs by educators and trained researchers, as well as the implementation of good laboratory practice (GLP) and the use of certified products. The RENAMA network started its activities in 2012, and was originally comprised of three central laboratories - the National Institute of Metrology, Quality and Technology (INMETRO); the National Institute of Quality Control in Health (INCQS); and the National Brazilian Biosciences Laboratory (LNBio) - and ten associated laboratories. In 2022, RENAMA celebrated its 10th anniversary, a milestone commemorated by the organisation of a meeting attended by different stakeholders, including the RENAMA-associated laboratories, academia, non-governmental organisations and industry. Ninety-six participants attended the meeting, held on 26 May 2022 in Balneário Camboriú, SC, Brazil, as part of the programme of the XXIII Brazilian Congress of Toxicology 2022. Significant moments of the RENAMA were remembered, and new goals and discussion themes were established. The lectures highlighted recent innovations in the toxicological sciences that have translated into the assessment of consumer product safety through the use of human-relevant NAMs instead of the use of existing animal-based approaches. The challenges and opportunities in accepting such practices for regulatory purposes were also presented and discussed.
Assuntos
Aniversários e Eventos Especiais , Laboratórios , Animais , Humanos , BrasilRESUMO
This study developed an air-liquid interface (ALI) corneal model using explants bovine eyes for ocular toxicity assessment of ten chemicals and seven hair straightening mixtures. It was successfully maintained physiologically viable and normal for six days. Both eye damage (GHS cat. 1) and irritating (GHS cat. 2) chemicals induced corneal injury in our model. However, cat. 2 irritants triggered moderate damage when compared to cat. 1 agents, which induced a marked cytotoxicity profile. The mixtures were also able to trigger viability reduction associated with histopathological changes in the corneal tissues, especially when the exposure was via aerosol particles. Thus, the chemical exposure microenvironment simulation seemed to provide more reliable toxicological data. Moreover, mixture-induced corneal damage correlated with increased ROS levels, suggesting a close correlation between tissue death and oxidative stress. Besides mixtures showing the potential to induce moderate/mild ocular toxicity, we could verify that the corneal tissue damage showed reversibility due to the recovery from the injury after exposure to some of the mixtures. Hence, our ex vivo corneal model seems to be a simple and cost-effective approach for future studies related to further investigating the reversibility of damage in the cornea triggered by chemicals and their mixtures.
Assuntos
Alternativas aos Testes com Animais , Neuropatia Óptica Tóxica , Bovinos , Animais , Testes de Toxicidade , Irritantes/toxicidade , Córnea/patologia , CabeloRESUMO
Inhibition of p53-MDM2 complex has been emerging as a strategy for antitumoral drug development considering the pro-apoptotic role of functional p53 in tumor cells. In our study, the prototype LQFM166 (2), designed through molecular simplification strategy inspired in the Nutlins compounds, was synthetized, characterized and the mechanisms of cell death were investigated. In addition, we estimated the starting doses for acute oral systemic toxicity tests according to the OECD Guidance Document No.129 - 3T3 NRU. The cytotoxic profile of LQFM166 (2) was determined in K-562â¯cells, a p53-null cell line, since previous studies also showed activity of LQFM166 (2) on this cells. After 24, 48 or 72â¯h of compound treatment, using MTT reduction assay, the IC50 values found were 100.1⯵M, 56.76⯵M and 45.11⯵M, respectively. LQFM166 (2) was cytotoxic for leukemia cells in a concentration-time-dependent manner. Cell death mechanisms studies of LQFM166 on K-562â¯cells, revealed that the compound induced cell cycle arrest, increased the expression of caspase 3/7, 8 and 9, cytochrome c, Bax, p21 and p27. Additionally, a decrease in the expression of the Bcl-2 and cyclin-B1 was observed. The apoptotic inducer profile of the compound was confirmed by phosphatidylserine externalization. Investigation of complexation of p53/MDM2 was carried out by ELISA assay using 3T3 cell, showing a decrease in the p53-MDM2 complex induced by the compound. Furthermore, the cytotoxicity in basal fibroblasts 3T3 was determined to estimate LD50. LQFM166 (2) reduced 3T3 cells viability with the IC50 of 185.3⯵M and estimated LD50 of 706.7â¯mg/kg (category 4 of GHS). The rationally designed of the prototype LQFM166 (2) induced cell death by apoptotic mechanisms in leukemic cells and showed MDM2 complexation antagonism in 3T3 cells.