Effects of argon and nitrogen plasma pulses on the skin and skin appendages in an in vivo animal model

BACKGROUND: For medical purposes, plasma can be generated from inert gaseous sources in a device by ultra-high-frequency generators and emitted to target tissue at a pulse duration in the milliseconds. OBJECTIVE: To evaluate argon and nitrogen plasma pulse-induced tissue reactions in the skin and skin appendages of an in vivo animal model. METHODS: Argon and nitrogen plasma pulses were non-invasively delivered to in vivo rat skin at various experimental settings. Specimens were histologically evaluated following hematoxylin and eosin and Masson's trichrome staining. RESULTS: At low-energy settings of 1.0, 1.5, and 2.0 J, nitrogen plasma treatments generated noticeable tissue coagulation at the depths of 31.5 +/- 8.3, 94.9 +/- 16.9, and 171.6 +/- 19.7 microm, respectively, at Day 0. At high-energy settings of 2.5 and 3.0 J, nitrogen plasma treatments generated marked tissue coagulation at the depths of 381.7 +/- 33.6 microm and 456.3 +/- 75.7 microm, respectively, at Day 0. CONCLUSIONS: Treatment with argon plasma induces microscopic changes in the epidermis, dermis, and sebaceous glands without generating excessive thermal injury, whereas that with nitrogen plasma elicits energy-dependent thermal coagulation in the epidermis and dermis with remarkable neocollagenesis.