TNF-α Expression and Plasma Cell and Macrophage Numbers in Traumatic Ulcers in a Rat Model Treated by Topical or Systemic Probiotic <i>L. casei Shirota</i>

<b>Introduction</b>: Live microorganisms, named probiotics, can improve overall physical well-being, particularly the oral cavity's health. <i>L. casei Shirota</i>, a popular probiotic, can influence the immune response by increasing the number of macrophages and plasma cells that play a role in traumatic ulcer healing. <b>Aims</b>: To determine the expression of tumor necrosis factor-alpha (TNF-α) and the varied number of plasma cells and macrophages on a traumatic ulcer animal model treated with topical or systemic administration of a probiotic <i>L. casei Shirota.</i> <b>Material and Methods</b>: Thirty-six healthy, 2-3-month-old male <i>Rattus norvegicus</i> weighing 175-250 gram, were designed into control and topical and systemic administration probiotic groups. The control group was treated with Aquadest 20 uL/20 gr, while topical probiotic and systemic administration probiotic groups were treated with 10,9x10⁷ cells/kg, respectively. A heated round burnisher tip was used to traumatize the inferior incisive fornix labial area. After 3 or 7 days, the animal models were terminated. Immunohistochemical examination, Hematoxylin eosin staining, and statistical analysis were performed to analyze the expression of TNF-α and the number of plasma cells and macrophages. <b>Results</b>: The Mann-Whitney and Tukey HSD tests indicated significant differences (<i>p</i> < 0.05) in the results for the three groups. It was observed that topical administration provides more remarkable results than systemic administration for the expression of TNF-α, the number of plasma cells, and the number of macrophages. <b>Conclusion</b>: Topical administration of <i>L. casei Shirota</i> demonstrates better results than systemic administration for healing traumatic ulcers.