The Role of Topical Thymoquinone in The Treatment of Acute Otitis Externa: An Experimental Study in Rats
The Journal of International Advanced Otology
Original Article Acute otitis externa (AOE) is the most common infection of the external auditory canal (EAC). High temperatures, humidity, trauma, absence of cerumen, excessive sweating, alkaline pH, and the use of a hearing aid are all risk factors in the development of AOE  . Although AOE is primarily a local disease, it may be more severe and invasive in cases where the patients' immune system is suppressed. Edema and sensitivity in the EAC are noted in otoscopic examinations  . The
... nations  . The most frequently isolated microorganism in cases of AOE is Pseudomonas aeruginosa, which has gram-negative properties and reproduces easily on a moist base  . Topical treatment is generally used in the treatment of AOE. When the infected area can be reached by topical drops, systemic antibiotics are not required  . Aminoglycosides, polymixin B, quinolones, and acetic acid are generally used as topical antimicrobial agents. The anti-inflammatory effects of these agents reduce edema and pain and can be used alone or combined with corticosteroids    . Thymoquinone (TQ) is an active constituent isolated from the Nigella sativa plant  . Previous studies have shown that the biological activity of Nigella sativa, which is used in traditional medicine, originates from the high ratio of TQ in the content  . Since it was first isolated, studies have shown anti-inflammatory, antioxidant, and anticarcinogenic activity [7, 8] . The aim of this experimental study was to compare the dose-related effect of TQ with other topical agents on AOE created in a rat model. OBJECTIVE: The aim of this experimental study was to compare the dose-related effect of topical thymoquinone (TQ) with other topical agents used in the management of acute otitis externa (AOE) in a rat model. MATERIALS and METHODS: Forty-eight male Wistar albino rats were divided into six groups each with eight rats per group. Group I was the control group with no external otitis, whereas external otitis were created in the other five groups (study groups). Dexamethasone, 0.1% TQ, 0.4% TQ, ciprofloxacin, and 0.9% saline (NaCl) drops was applied once daily in Groups II-VI, respectively. The treatment was administered regularly for 10 days. Pathologic and microbiologic evaluation were performed. Pathologically, the thicknesses of the stroma and the epithelium in the external auditory canal (EAC) were measured using an occulometer. Edema in the stroma, density of inflammatory cells and blood vessels, presence of fibroblasts, and changes in collagen fibers in the EAC were evaluated in five different areas to obtain the area of highest concentration and classified into four grades (0=no change, 1=mild, 2=moderate, 3=severe). RESULTS: The higher concentration of TQ (0.4%) was more effective than dexamethasone and 0.1% TQ with respect to antibacterial and the anti-inflammatory properties. CONCLUSION: TQ, particularly at a concentration of 0.4%, may be considered for topical application alone in the treatment of AOE, without any requirement for a combined treatment.