Necropsy in Mouse Research.

Necropsy is the postmortem examination of an animal's body. Experiments on laboratory animals are performed to gather scientific data relevant to basic and, even more often, translational research, mainly in the field of translational medicine. A necropsy conducted on laboratory animals subjected to experimental research provides an opportunity to exhaustively explore pathological processes that took place during life. In order to achieve that goal, procedures of biomaterial collection should be performed timely, bearing in mind the inevitable process of postmortem tissue decay, and precisely, to avoid mechanical tissue damage.In this chapter, procedures of collecting organs and tissue in a way that ensures the preservation of the organ structure, tissue organization, morphological characteristics of cells, and last but not least, intracellular protein and nucleic acid content and chromosome organization are going to be described step by step.

Effects of Multimodal Therapy, Blinding, and Multi-laboratory Protocol Conduct on the Robustness of the Rat Model of Adjuvant Induced Arthritis.

BACKGROUND/AIM: The aim of this study was to investigate the effects of multimodal therapy comprising buprenorphine (BUP) and indomethacin (IND) on key translational parameters in the rat adjuvant induced arthritis (AIA) model. Furthermore, we investigated the difference between visual assessment scores and histology scores generated by blinded and non-blinded assessors and the robustness and generalizability of results by conducting a multi-laboratory study. MATERIALS AND METHODS: The experiment was terminated on day 26 after 11 days (days 15-25) of voluntarily ingested buprenorphine and 7 days of gavage delivered indomethacin treatment (days 19-25). The treatment effects were assessed on the last day of the study, relying on body weight assessment, serum concentrations of α1- acid glycoprotein, and assessment of affected hind paws swelling, in-life and post mortem. RESULTS: Across two laboratories, the combined analgesic treatments had minimal effects on the measured model parameters indicating that multimodal treatment did not affect the translatability of the model. We found an improvement in clinical scores (a negative change in scores) in nearly all medicated animals when scored informed, whereas it was essentially 50:50 for the blinded scorings and no difference between the blinded and informed histological scoring. CONCLUSION: The present results support the use of more effective analgesic treatment regimens and the good practice recommendations advocating blinding as a mandatory practice in conduct of preclinical in vivo efficacy studies. In spite of minor differences between results obtained at the two sites, there was good agreement between them indicating robustness of the AIA model.

Claudins: Beyond Tight Junctions in Human IBD and Murine Models.

Claudins are transmembrane proteins constituting one of three tight junction protein families. In patients with inflammatory bowel disease (IBD), disease activity-dependent changes in expression of certain claudins have been noted, thus making certain claudin family members potential therapy targets. A study was undertaken with the aim of exploring expression of claudins in human disease and two different animal models of IBD: dextrane sulfate sodium-induced colitis and adoptive transfer model of colitis. The expression of sealing claudin-1, claudin-3, claudin-4, and claudin-8, and pore-forming claudin-2 in humans and rodents has been evaluated by immunohistochemistry and quantitative polymerase chain reaction. Claudins were expressed by epithelial and cells of mesodermal origin and were found to be situated at the membrane, within the cytoplasm, or within the nuclei. Claudin expression by human mononuclear cells isolated from lamina propria has been confirmed by Western blot and flow cytometry. The claudin expression pattern in uninflamed and inflamed colon varied between species and murine strains. In IBD and both animal models, diverse alterations in claudin expression by epithelial and inflammatory cells were recorded. Tissue mRNA levels for each studied claudin reflected changes within cell lineage and, at the same time, mirrored the ratio between various cell types. Based on the results of the study, it can be concluded that 1) claudins are not expressed exclusively by epithelial cells, but by certain types of cells of mesodermal origin as well; 2) changes in the claudin mRNA level should be interpreted in the context of overall tissue alterations; and 3) both IBD animal models that were analyzed can be used for investigating claudins as a therapy target, respecting their similarities and differences highlighted in this study.