Histopathological Analysis of Brains from Dogs Infected with Canine Distemper Virus.

We describe the use of conventional histology and immunohistochemistry against canine distemper virus (CDV) to examine the brains of domestic dogs with a confirmed diagnosis of CDV infection. Histologically, to identify the main typical lesions, we used conventional H&E stain; to evaluate the progressive demyelination, we used Luxol Fast Blue stain; and to identify the presence of viral particles in these affected regions, we used immunohistochemistry against CDV. We confirm that the histopathological analysis of brains of distemper-infected dogs is a powerful tool to evaluate the typical brain lesions and could be used as an interesting natural model to continue studying the pathogenesis of canine distemper in different species and/or other morbillivirus infections, like measles.

Jejunum-derived NF-κB reporter organoids as 3D models for the study of TNF-alpha-induced inflammation.

Inflammation is an important process for epithelial barrier protection but when uncontrolled, it can also lead to tissue damage. The nuclear factor-kappa light chain enhancer of activated B cells (NF-κB) signaling pathway is particularly relevant in the intestine, as it seems to play a dual role. Whereas NF-κB protects intestinal epithelium against various noxious stimuli, the same pathway mediates intestinal inflammatory diseases by inducing pro-inflammatory gene expression. The availability of appropriate in vitro models of the intestinal epithelium is crucial for further understanding the contribution of NF-κB in physiological and pathological processes and advancing in the development of drugs and therapies against gut diseases. Here we established, characterized, and validated three-dimensional cultures of intestinal organoids obtained from biopsies of NF-κB-RE-Luc mice. The NF-κB-RE-Luc intestinal organoids derived from different intestine regions recreated the cellular composition of the tissue and showed a reporter responsiveness similar to the in vivo murine model. When stimulated with TNF-α, jejunum-derived NF-κB-RE-Luc-reporter organoids, provided a useful model to evaluate the anti-inflammatory effects of natural and synthetic compounds. These reporter organoids are valuable tools to explore the epithelial TNF-α-induced NF-κB contribution in the small intestine, being a reliable alternative method while helping to reduce the use of laboratory animals for experimentation.