Histological Alterations in the Internal Organs of Wistar Han Rats (Rattus norvegicus) Euthanized by Five Different Methods.

Selecting a method of euthanasia is an important step in designing research studies that use animals; euthanasia methods must be humane, cause minimal pain and suffering to the animal, and preserve the tissue architecture of the organs of interest. In this study, we evaluated the histomorphology of the internal organs (lung, spleen, heart, kidney, liver, brain, and adrenal gland) of rats submitted to five different methods of euthanasia, with the goal of determining which protocol caused the least alteration of histomorphology. Twenty adult Wistar Han rats (Rattus norvegicus) were divided into 5 groups of 4 rats each (2 females and 2 males) and were euthanized by CO2 or isoflurane inhalation, sodium thiopental or xylazine plus ketamine overdose, or decapitation. All euthanasia was performed in accordance with published guidelines and local legal require- ments. Necropsy was performed immediately after euthanasia. Specific internal organs were removed and placed in formalin and submitted for routine histologic processing. Histomorphological examination of hematoxylin and eosin-stained tissues revealed circulatory alterations in multiple organs, predominantly congestion in multiple tissues, pulmonary hemorrhage, and hepatic degeneration. The euthanasia methods that induced the most severe alterations were exposure to CO2 and anesthetic overdose with xylazine plus ketamine or sodium thiopental. Euthanasia by overexposure to isoflurane caused less damage, and the alterations were of minimal severity. Decapitation resulted in the lowest incidence of lesions in multiple organs but due its traumatic nature, it caused the highest incidence of pulmonary hemorrhage. In selecting a method of euthanasia, factors to consider are the species of animal, the purpose of the research, and the practical ability to perform the procedure to achieve maximal animal welfare without iatrogenic changes that could compromise the outcome and reproducibility of the study.

Antiangiogenic Targets for Glioblastoma Therapy from a Pre-Clinical Approach, Using Nanoformulations.

Glioblastoma (GBM) is the most aggressive tumor type whose resistance to conventional treatment is mediated, in part, by the angiogenic process. New treatments involving the application of nanoformulations composed of encapsulated drugs coupled to peptide motifs that direct drugs to specific targets triggered in angiogenesis have been developed to reach and modulate different phases of this process. We performed a systematic review with the search criterion (Glioblastoma OR Glioma) AND (Therapy OR Therapeutic) AND (Nanoparticle) AND (Antiangiogenic OR Angiogenesis OR Anti-angiogenic) in Pubmed, Scopus, and Cochrane databases, in which 312 articles were identified; of these, only 27 articles were included after selection and analysis of eligibility according to the inclusion and exclusion criteria. The data of the articles were analyzed in five contexts: the characteristics of the tumor cells; the animal models used to induce GBM for antiangiogenic treatment; the composition of nanoformulations and their physical and chemical characteristics; the therapeutic anti-angiogenic process; and methods for assessing the effects on antiangiogenic markers caused by therapies. The articles included in the review were heterogeneous and varied in practically all aspects related to nanoformulations and models. However, there was slight variance in the antiangiogenic effect analysis. CD31 was extensively used as a marker, which does not provide a view of the effects on the most diverse aspects involved in angiogenesis. Therefore, the present review highlighted the need for standardization between the different approaches of antiangiogenic therapy for the GBM model that allows a more effective meta-analysis and that helps in future translational studies.