Investigating the Role of Antioxidant Gel (AO) on Wound Healing: An In Vivo Study

Abstract

Prolonged inflammation and oxidative stress are deleterious to periodontal healing. Anti-inflammatory and antioxidant agents have increasingly been researched and used to promote efficient healing. This in vivo study compared the effects of Periosciences antioxidant gel (AO) on wound healing following gingival augmentation with acellular dermal matrix (Alloderm™) to the gold standard, Chlorhexidine mouth rinse (CHX) and untreated control.

Methods and materials

One investigator subjected Sixty Sprague Dawley rats to the same IACUC-approved surgical procedure. Envelope flaps were created in the lower incisor region, and AllodermTM was inserted. Sutures were used to close the surgical site. Rats were randomly assigned to receive the application of AO or 0.12% CHX to the surgical site twice daily. The control group had no agent applied. Animals were assessed twenty-four and seventy-two hours following surgery, and weights were recorded pre and post-surgery for all animals.

Surgery site tissues for histological analysis and real-time polymerase chain reaction (RT-PCR) were obtained to quantify the gene expression of interleukin 1 (ILl ), tumor necrosis factor-alpha (TNFa), myeloperoxidase (MPO) and superoxide dismutase (SOD). A double-blind analysis of soft tissue healing based on randomized clinical photos was completed. Normally distributed data was analyzed by ANOVA followed by Bonferroni posthoc testing. For non-normally distributed data, Kruskal Wallis and Mann Whitney tests were used.

Results

Based on a double-blind clinical assessment, rats in the AO group scored significantly better than those in the CHX and control groups when comparing gingival color, granulation tissue, swelling and graft exposure (p<0.05). However, the degree of epithelization was inconclusive. All rats lost weight in the first twenty-four hours following surgery. Rats treated with AO and CHX regained significantly more weight at seventy-two hours than control rats (p= 0.04 and 0.009, respectively). TNFa expression was significantly higher in the AO group compared to CHX (p=0.027) and controls (p=0.018) at twenty-four hours. The AO group also had significantly higher levels of antioxidant enzyme (SOD) expression in the first twenty-four hours compared to CHX (p= 0.021).

Discussion

This randomized-control in vivo study demonstrated that applying topical agent AO or CHX led to less post-operative pain in rodents, based on their weight recovery at seventy-two hours. Image analysis indicated that animals treated with AO had less swelling and healed faster than CHX and control­ treated animals. Despite significantly increasing pro-inflammatory marker TNFa, the antioxidant enzyme SOD was expressed to counteract oxidative stress and reduce inflammation in the AO-treated rats. An increase in SOD was not apparent in the CHX group; it is known that this agent inhibits fibroblasts, a source of SOD. Therefore, the rats in the CHX group had overt inflammation and reduced antioxidant defense.

Conclusions

Topical agents appear to be beneficial to soft tissue healing and post-operative comfort. Rats treated with AO show earlier signs of recovery and less inflammation than those treated with CHX and control. We postulate that AO promoted an earlier inflammatory process while counteracting oxidative stress with increasing antioxidant mechanisms such as enzyme SOD.