TNF-α Expression and New Epithelial Thickness in the Skin of Mice (Mus musculus) Infected MRSA by Medical Plasma Treatment Sri Darmawati, a,b,c, * Def Nurul Hayati, a,b Mudyawati Kamarudin, a,b,c & Gela Setya Ayu Putri b,d a Department of Clinical Laboratory Science, Universitas Muhammadiyah Semarang, Indonesia; b Interdisciplinary Research Laboratory for Experimental Plasma Medicine (iPlasmed), Universitas Muhammadiyah Semarang, Indonesia; c Muhammadiyah Research Network for Plasma Medicine (M-Plasmed), Semarang, Indonesia Faculty of Nursing and Health Sciences, Muhammadiyah University, Indonesia; d Department of Medical Laboratory Technology, Faculty of Nursing and Health Faculty, Universitas Muhammadiyah Semarang, Indonesia *Address all correspondence to: Dr. Sri Darmawati, MSi, Department of Clinical Laboratory Science, Universitas Muhammadiyah Semarang, Jl. Kedungmundu Raya No.18, Semarang, 50273, Central Java, Indonesia; Tel.: +62-24-76740296, ext. 1102; Fax: +62-24-76740291, E-mail: ciciekdarma@unimus.ac.id ABSTRACT: Chronic wounds develop as a result of infection, commonly carried on by bac- teria and form bioflms. MRSA is a kind of bacteria that can form bioflms. Recently, medical plasma technology has been applied to accelerate wound healing. The objective of the research was to investigate the response of cutaneous wounds in MRSA-infected animals to contact and non-contact therapy using medical plasma argon jet-type with histopathological and molecular approaches. Argon gas, with a purity of 99.995%, is utilized as a carrier gas for generating plasma medical at a fow rate of 1 standard liter per minute (slm). This experiment was divided into 4 treatment groups, K (infected wound without plasma treatment), CP (5 mm plasma treatment), NCP (20 mm plasma treatment), and CP-NCP (infected wound with 5 mm and 20 mm plasma combination treatment). The result of the observation obtained that contact plasma from day 3 to day 10 can remove bacterial bioflm and that non-contact plasma treatment from day 11 to day 16 is efective to accelerate wound healing. At day 17, the macroscopic bioflm area in the CP-NCP group began to decrease with an increasing percentage of re-epithelialization, and no necrotic cells were observed. TNF-α levels were observed signifcantly lower in the CP-NCP group at day 17 compared with other groups. In conclusion, contact-non-contact (CP-NCP) treatment is sug- gested for the management of chronic infections since it is benefcial for removing the bacterial bioflm layer and can promote wound healing. KEY WORDS: animal model, chronic wound, plasma medicine, MRSA, combination treatment I. INTRODUCTION The major cause of chronic wounds is bacterial infection, which results in the production of bioflms. 1 Staphylococcus aureus (S. aureus) is the most common pathogen bacterial detected in patients with wound infection. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the clinically identifed strains of S. aureus that has been reported to be resistant to methicillin. MRSA has been found in the skin tissue of individuals with 1947-5764/22/$35.00 © 2022 by Begell House, Inc. www.begellhouse.com 45 Plasma Medicine, 12(4):45 – 56 (2022)