Pathologic and Environmental Studies Provide New Pathogenetic Insights Into Ringtail of Laboratory Mice

Abstract

Ringtail is a pathologic condition of laboratory rodents characterized by annular constrictions of the tail. Traditionally, it is classified as an environmental disorder caused by low relative humidity, but other factors (temperature, dietary deficiencies, genetic susceptibility, and caging type) have also been proposed. Twenty litters of mice with ringtail lesions occurred from September 2010 to August 2013 in a facility located in the northern Italy. Mice were maintained under controlled environmental conditions and fed a standard diet. Retrospective analysis of environmental data (relative humidity, temperature) was carried out. Gross, histopathologic, scanning, and transmission electron microscopy examination of tails and limbs was performed. The incidence of ringtail was 0.075% (20/26 800) of all weaned litters over the 3-year period of examination. Temperature and relative humidity remained within accepted limits in all cases except one. We observed annular constrictions in tail, digits of pes, crus, and antebrachium in 116 (100.0%), 47 (40.5%), 11 (9.5%), and 2 (1.7%) of 116 affected mice, respectively. Histologic and ultrastructural examination revealed abnormal keratin desquamation and presence of a keratin ring encircling the tail, causing progressive strangulation of the growing tail with subsequent compression and ulceration of underlying soft tissues, resulting in circulatory changes (edema, hyperemia, thrombosis, hemorrhages), ischemic necrosis, and eventually auto-amputation distal to the constriction. On the basis of our findings, we suggest a disorder of cornification as the primary lesion of ringtail in mice. The cause of these cases, however, remained undetermined, even though traditional etiologic factors (relative humidity, temperature, diet, caging type) were reasonably excluded.

Interleukin‐1β injection causes loss of tail tips in neonatal mice

“…Figure 1 includes two photos of such mice—a male and female. As can be seen, the tips of the tails were black and contained small constrictions similar, at least superficially, to those observed in “ringtail” (Recordati et al, 2015). One explanation for our findings is thus that neonatal IL‐1β induces “ringtail” in mice.…”

“…One explanation for our findings is thus that neonatal IL‐1β induces “ringtail” in mice. It is worth noting, however, that the etiology of ringtail is poorly understood, beyond an association with ambient humidity (Recordati et al, 2015). Another possibility is that IL‐1β administration caused an inflammatory‐induced “tail necrosis” or “tail tip necrosis.”…”

A pilot study: tail tip lesions in dairy cows – an unnoticed animal welfare issue?

“…It is associated with slatted flooring systems (Schrader et al, 2001;Madsen and Nielsen, 1985;Drolia et al, 1990) or feeding high-energy ratios (Kordowitzki, 2015) as subacute ruminal acidosis triggers the onset of systemic inflammation, especially within the acra (Abdela, 2016). However, tail tip inflammation is reported to appear in many other species as well, such as buffalo (Barakat et al, 1960), rodents (Crippa et al, 2000;Recordati et al, 2015), cats (Bridle and Littlewood, 1998), deer (Ferguson et al, 2016), or pigs (Reiner et al, 2021). The consensus for all species regarding tail lesions is that the pathogenesis is not fully understood yet.…”

Strukturelle und funktionelle Charakterisierung Filaggrin/Hornerin defizienter (FlgHrnr-/-) Mäuse

“…Als mögliche Erklärung der diskrepanten Beobachtungen lassen sich wiederum Unterschiede in den Haltungsbedingungen vermuten. Als Ursache des Verlustes der Schwanzspitze werden Einschnürungen, welche während des Wachstums aufgrund einer rigiden Haut entstehen, und eine dadurch verursachte Durchblutungsstörung mit folgender Nekrose vermutet (Recordati et al 2015).…”