Evaluation of topical oclacitinib and nail trimming as a treatment for murine ulcerative dermatitis in laboratory mice

PLOS ONE, 2022 · DOI: https://doi.org/10.1371/journal.pone.0276333 · Published: October 18, 2022

Veterinary Medicine Research Methodology & Design Dermatology

Simple Explanation

This study investigates the effectiveness of topical oclacitinib, a drug used for allergic dermatitis, in treating ulcerative dermatitis (UD) in mice. UD is a common skin disease in certain mouse strains, causing scabs, crusts, and intense itching. The researchers compared topical oclacitinib combined with nail trimming to standard treatments. Mice with UD were divided into three groups: nail trimming alone, nail trimming plus standard treatment (meloxicam and topical antibiotic), and nail trimming plus topical oclacitinib. The severity of UD was assessed at the beginning of the study, and then again after 7 and 14 days of treatment. The study found that all three treatment groups showed improvement in UD scores over time. However, there was no significant difference in the average UD scores between the three treatment groups at any point during the study. This suggests that topical oclacitinib did not provide additional benefits beyond nail trimming or the standard treatment.

Study Duration

14 Days

Participants

45 C57BL/6 or C57BL/6-background strain mice (11 males and 34 females)

Evidence Level

Not specified

Key Findings

1
Mean UD scores decreased from day 1 to day 7 and from day 1 to day 14 for all treatment groups, indicating improvement in skin lesions regardless of the treatment.
2
There was no significant difference in mean UD score between the treatment groups (nail trim only, nail trim plus meloxicam and topical antibiotic ointment, or nail trim plus topical oclacitinib) at any time point (day 1, 7, or 14).
3
Approximately 50-70% of animals reached a score of 0 (complete resolution of skin lesions) within 14 days, depending on the treatment group, with the nail trim plus meloxicam and topical antibiotic ointment group showing slightly faster resolution.

Research Summary

This study evaluated the efficacy of topical oclacitinib, in conjunction with nail trimming, for treating murine ulcerative dermatitis (UD) compared to nail trimming alone or nail trimming combined with meloxicam and topical antibiotic ointment. The study found that all three treatment regimens resulted in significant improvement of UD lesions over time. However, there was no significant difference in mean UD scores between the three groups at any of the assessed time points. The results suggest that topical oclacitinib, as used in this study, does not provide a significant advantage over nail trimming alone or the institutional standard treatment for managing murine UD.

Practical Implications

Treatment Protocol

Nail trimming remains an effective first-line treatment for murine ulcerative dermatitis.

Further Research

Further research is warranted to optimize the use of oclacitinib, including exploring different administration routes, dosages, and diluents.

JAK Inhibitors

JAK inhibitors may still be a viable alternative when NSAIDs or antibiotics are not suitable due to potential interference with research studies.

Study Limitations

1
The potential irritant effect of repeated DMSO administration may have masked some of the benefit of topical oclacitinib in terms of itching and inflammation.
2
Capturing improvement was challenging for more severe lesions which take longer to have the improvement reflected in the UD score.
3
The treatment duration of 5 days described here was selected to mimic our standard treatment which typically includes 5 days of topical triple antibiotic ointment

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