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Wound Healing and TopicAid® :
I. Emu Oil's Permissive Effects on the
Anti-Bacterial Actions of Benzyl Alcohol

Technical Bulletin September 2003 TB3-03

Introduction

TopicAid®, a topical spray that contains emu oil as one of its ingredients, promotes healing of surgical incisions, mechanical wounds and abrasions, and burns. Numerous anecdotal reports exist testifying to the anti-inflammatory effects of emu oil. However, there are very few scientifically based studies on this subject. In one of the very few such investigations, Snowden et al. (1997) evaluated numerous emu oil formulations, reporting that 80% of them significantly reduced symptoms of adjuvant-induced arthritis in rats. Transdermal application of emu oil formulations in fact showed an efficacy equivalent to orally administered ibuprofen (40 mg/kg). In mice, topically applied emu oil significantly ameliorated acute auricular inflammation resulting from exposure to croton oil (Lopez, et al. 1999). The specific components of emu oil creating these anti-inflammatory properties have not yet been determined.


TopicAid® has been proven to have substantial anti-microbial properties to common bacterial and yeast pathogens such as Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, Candida albicans and Streptococcus agalactiae (See Lucid Med Tech II Technical Bulletin TB2-03, accessed at www.topicaid.com). While the mode of action of TopicAid® and other emu-oil containing formulations has not been identified, emu oil may function to blunt the deleterious effects on healthy, healing tissues of otherwise powerful anti-microbial agents in emu oil and emu-oil based formulations (e.g. TopicAid®). This technical bulletin addresses one of the underlying modes of action of TopicAid® on healing tissues. TB3-03 is based on the first of a series of experiments using healing skin of the rat, carried out by veterinarians specializing in wound care in the College of Veterinary Medicine at the University of Missouri-Columbia.

Methodology Employed

As an overview, the methodology for this study involved the humane induction of superficial skin burns in rats, after which the time course and gross anatomical appearance of the healing of these wounds was recorded in either groups receiving treatment with TopicAid®or with modified formulations of this product without emu oil.


Forty male rats (~275 grams) were individually housed in an animal care facility approved by the Association for Assessment and Accreditation of Laboratory Animal Care. All procedures were, in addition, approved by the Institutional Animal Care and Use Committee of the University of Missouri-Columbia. Each rat was anesthetized (isoflurane delivered in O2) and the upper surface of the trunk was then shaved and prepared for aseptic surgery using chlorhexidine. To clearly identify the original site of burn induction, a permanent 2cm2 grid was placed on the skin using a tattoo marker. A CO2 Laser (10 watts, 0.2 exposure time) was then used to create 2 cm2 artificial-thickness wounds after the technique of Yang et al, 2001. To ensure the comfort of the animal in the immediate post-operative recovery period, analgesia was provided by subcutaneous buprenorphine (0.1 mg/kg).

In the phase of the studies reported here, populations being compared consisted of 20 rats whose wounds were treated with topical application of TopicAid® spray (Group TA), and 20 rats identically treated, but with TopicAid? spray minus emu oil, one of the spray?s major ingredients (Group TA-minus). The experimental protocol consisted of TA or TA-minus treatments of 0.5 mls per treatment, which were made twice daily for the duration of the 21 day study. Wounds were left unbandaged. Daily visual assessments were made of numerous wound and healing characteristics. Measurements were made at days 7, 14, and 21. At the end of study period, rats were euthanized using CO2. Of the initial 40 rats, 4 mortalities occurred. Post mortem identified causes of death unrelated to experimental treatment (bowel obstruction from ingestion of bedding material).


This study was conducted as a ?blind? investigation ? that is, the experimenters were not told of the various solutions they were applying, which were identified simply as Solution A, Solution B, etc.

Findings of the Study

The intent of this study was to determine whether the emu oil in TopicAid® had any ameliorating of the effects on healing rat skin of the benzyl alcohol in the standard TopicAid®formulation. As evident in figure 1, only 5.0% of the rats treated with the standard TopicAid® formulation showed reddened, dry healing skin, which indicates continuing inflammation and dehydration. In complete contrast, fully 80.0% (16 of 20) of the rats treated with the TopicAid® formulation lacking emu oil showed severe inflammation and dehydration of the skin.

Figure 1. Incidence of skin inflammation and dehydration following daily topical treatment of laser-induced burns using standard TopicAid®formulation and using TopicAid® formulation without emu oil.

emu-oil-topicaid

Interpretations and Conclusions

TopicAid® is strongly anti-microbial (bacteria and yeast), due in part to the benzyl alcohol in the commercial formulation. While alcohols have antibacterial properties well known for centuries, they also are irritants, are toxic to healthy tissues as well as the microbes they are intended to treat, and are dehydrating agents. It was therefore not surprising that the TA-minus formulation was a strong irritating and dehydrating agent.


The ameliorating effect of emu oil on skin inflammation and irritation caused by the benzyl alcohol was quite striking in these experiments. Whereas 80% of rats experienced skin inflammation and dryness in the TA-minus group, only 5% of the TA group receiving the normal formulation experienced similar irritation and dehydration.


It is concluded that emu oil has a ?permissive? effect when combined with benzyl alcohol, allowing the strongly anti-microbial properties of the benzyl alcohol in TopicAid®to destroy pathogenic bacteria and yeast leading to wound infection without causing the expected inflammation and dehydration of the healthy, regenerating tissue.

References

Lopez, A., Sims, D.E., Ablett, R.F., et al. (1999) Effect of emu oil on auricular inflammation induced with croton oil in mice. AJVR 60(12):1558-1561.
Snowden, J.M., Whitehouse, M.W. (1997) Anti-inflammatory activity of emu oils in rats. Inflammopharm 1997;5:127-132.

Yang, L., Chan, T., Demare, J., et al. (2001) Healing of burn wounds in transgenic mice over expressing transforming growth factor-?1 in the epidermis. Am J Pathol 2001;159:2147-2157.

TopicAid® is a registered trademark of Lucid Med Tec II, Ltd.