Phenytoin Effects on Palatal Wound Healing: Selective Gene Expression Analysis

Objectives: In a recent prospective clinical study, we found improved clinical healing of standardized excisional palatal wounds with topical phenytoin (PHT) application. To better understand the involved mechanisms, a targeted molecular investigation was performed.
Methods: 20 systemically and periodontally healthy adults were included and randomly allocated into two equal groups. One 6mm diameter wound (posterior) and one 4mm wound (anterior), each 1.5mm depth, were created on both sides of the palate using custom stent and biopsy punches. Wounds on one randomly chosen side received PHT (test) and on the other received carrier alone (control). Posterior undisturbed wounds were used to evaluate clinical healing on postoperative Day-1, -5, -14 and -21. Biopsies were harvested from the anterior wounds, either on Day-1 (Group-1) or on Day-5 (Group-2), and were used for selective quantitative mRNA expression analysis.
Results: According to our previous oral wound healing transcriptome study results, seven target mRNAs were selected. The analyzed genes were PGF, CSTB, SERPINB1, IL-33, C2CD4A, SLC16A1 and LYPD6B. qPCR analysis revealed significant differences between Day-0 (baseline) and Day-1 or Day-5 wounds in both groups, for all tested genes. However, there was no significant difference between groups. LYPD6B was the only gene with decreased expression in healing wounds, consistent with our previous findings. Expression of C2CD4A was much more elevated in PHT treated wounds (Day-5) than in control treated wounds. The temporal changes of C2CD4A expression appear to be opposite between PHT and control treatment.
Conclusions: Topical PHT application on standardized excisional palatal wounds results in improved objective clinical outcomes and different gene expression pattern. Based on this preliminary qPCR analysis, we expect that whole transcriptome analysis will provide novel data on the dynamic changes in gene expression during the early stages of oral wound healing and the molecular effects of PHT on wounded oral mucosa.