The assessment of the concentration of candidate cytokines in response to conjunctival-exposure of atmospheric low-temperature plasma in an animal model

Abstract Background Atmospheric Low-Temperature Plasma (ALTP) can be used as an effective tool in conjunctival cyst ablation, but little is known about how conjunctival ALTP-exposure affects the concentration of inflammatory mediators and also the duration of inflammatory responses. Methods We used 8 female adult Lewis rats that were followed up in 4 groups. The right eye of each rat was selected for the test, whereas the left eye was considered as a control. The ALTP was generated and used to target 3 spots of the conjunctiva. The digital camera examinations were performed to follow-up the clinical outcomes after ALTP exposure. Tear and serum samples were isolated—at 2 days, 1 week, 1 month, and 6 months after treatment—from each rat and the concentration of candidate pro-inflammatory (i.e. IL-1α, IL-2, IL-6, IFN-γ, and TNF-α) and anti-inflammatory cytokines (i.e. IL-4 and IL-10) were measured using flow cytometry. Results The external and digital camera examinations showed no ocular surface complications in all ALTP-exposed rats after 1 week. The analyses revealed that the ALTP transiently increases the concentration of pro-inflammatory cytokines—IL-1α and IL-2 in tear samples in 1 week and 2 days after exposure, respectively; no differences were observed regarding other pro- and anti-inflammatory cytokines in the tear or serum samples. Conclusions ALTP can probably be used as a minimally-invasive therapeutic method that triggers no permanent or continual inflammatory responses. The results of this study might help the patients to shorten the consumption of immunosuppressive drugs, e.g. corticosteroids, that are prescribed to mitigate the inflammation after ALTP-surgery.