Early Healing of Oral Soft Tissues: a Clinical and Biomolecular Analysis. Part III

The purpose of the present study is to evaluate the effect of Hyaluronic acid application in the gene expression profile and cellular behavior in the early wound healing process -24 hours after injury- of the oral soft tissues.

Although it has been demonstrated the role of HA in many different biological process related with tissue repair and regeneration, specific mechanisms involved in the early wound healing process in the oral soft tissues remains unclear. A recent in vitro study evaluated the effects of two HA formulations on human oral fibroblasts involved in soft tissue wound healing/regeneration. The authors demonstrated that the investigated HA formulations maintained the viability of oral fibroblasts and increased their proliferative and migratory abilities. Moreover, enhanced expression of genes encoding type III collagen and transforming growth factor-β3, characteristic of scarless wound healing. Interestingly, TGFB1 remains unchanged. Moreover, compared to untreated control cells, either HA preparation upregulated the expression levels of COL3A1 in both HPFs and HGFs at 24 hour, whereas no effect on COL1A1 mRNA levels was detected The HAs upregulated the expression of genes encoding pro-proliferative, pro-migratory, and pro-inflammatory factors, with only a moderate effect on the latter in gingival fibroblasts. However, in vitro experiments have certain limitations. HA would undergo degradation to lower MW molecules following hyaluronidase activity during the post-operative period and will thus exert additional or even opposing effects on the wound repair process.28 To highlight, is the fact that in the latest years, the translational medicine focuses in research concerning scar-free wound healing tissues repair mechanisms and regarding this, it has been proposed that HA plays an important role in the fast and scarless fetal wound healing seeing during the first and second trimester. Therefore, the aim of the present pilot study will be to evaluate the effect of hyaluronic acid application on gene expression and cellular behavior in the early wound healing process of gingival tissues. The second aim of the present work will be to evaluate the effect of HA in the wound healing clinical response. Our hypothesis is that HA modifies the expression of genes related with the early wound healing response and the behavior of the main cells involved in this biological process: fibroblasts; stimulating and accelerating their wound healing potential.

periodontal surgery + HA application + buccal attached gingival (G) biopsies 24 hr after surgical procedure

Periodontal surgery will be performed and 24 hr after the surgical procedure a 2mm punch biopsy will be harvested at the level of the buccal attache gingiva (G).

HA will be applied at the end of the surgical procedure, at the level of the vertical released incisions (VRIs) and over VRIs

Total RNA from biopsies or cell cultures was extracted using TRIzol reagent Quantitative real-time PCR (qRT-PCR) cDNA was generated and cDNA obtained were used for amplification of wound healing related genes using the appropriate TaqMan gene expression assay kits.

Assessed with a clinical index (EHS- Early wound healing score). This score assessed clinical signs of re-epithelialization (CSR), clinical signs of haemostasis (CSH), and clinical signs of inflammation (CSI). Since complete wound epithelialization was the main outcome, the CSR score was weighted to be 60% of the total final score. Accordingly, a score of 0, 3, or 6 points was possible for the assessment of CSR, whereas scores of 0, 1, or 2 points were possible for CSH and CSI. Higher values indicated better healing. Accordingly, the score for ideal early wound healing was 10.

Inclusion Criteria: patients that required periodontal surgery; patients age between 30-60 years; patients with full mouth plaque score and full mouth bleeding score < 15%; patients with a good general healthy status; patients without any medicaments or drug consumption that can affect the healing process; non-smoking patients. Exclusion Criteria: patients in pregnancy; patients in lactation period; patients with consumption of antibiotics or anti-inflammatory drugs in the previous six months; patients with systemic diseases.

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