Effects of antibiotics and steroid on middle ear mucosa in rats with experimental acute otitis media

Inner ear disturbances related to middle ear inflammation

The inner and middle ear are connected mainly through round and oval windows, and inflammation in the middle ear cavity can spread into the inner ear, which might induce a disturbance. In cases with intractable otitis media, attention should also be paid to symptoms related to the inner ear. In this paper, middle ear inflammation and related inner ear disturbances are reviewed with a focus on representative middle ear diseases (such as acute otitis media, chronic otitis media, otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitis, eosinophilic otitis media, cholesteatoma with labyrinthine fistula, and reflux-related otitis media). Their clinical concerns are then discussed with reference to experimental studies. In these diseases, early diagnosis and adequate treatment are required to manage not only middle ear but also inner ear conditions.

Anti-inflammatory and anti-oxidative effects of alpha-lipoic acid in experimentally induced acute otitis media

Objectives:

To investigate the anti-inflammatory, anti-oxidative and tissue protective effects, as well as the potential therapeutic role, of alpha-lipoic acid in experimentally induced acute otitis media.

Methods:

Twenty-five guinea pigs were assigned to one of five groups: a control (non-otitis) group, and otitis-induced groups treated with saline, penicillin G, alpha-lipoic acid, or alpha-lipoic acid plus penicillin G. Tissue samples were histologically analysed, and oxidative parameters in tissue samples were measured and compared between groups.

Results:

The epithelial integrity was better preserved, and histological signs of inflammation and secretory metaplasia were decreased, in all groups compared to the saline treated otitis group. In the alpha-lipoic acid plus penicillin G treated otitis group, epithelial integrity was well preserved and histological findings of inflammation were significantly decreased compared to the saline, penicillin G and alpha-lipoic acid treated otitis groups. The most favourable oxidative parameters were observed in the control group, followed by the alpha-lipoic acid plus penicillin G treated otitis group.

Conclusion:

Alpha-lipoic acid, with its antioxidant, anti-inflammatory and tissue protective properties, may decrease the clinical sequelae and morbidity associated with acute otitis media.

Preoperative antibiotic and steroid therapy and hearing loss caused by semicircular canal transection in pseudomonas otitis media

OBJECTIVE: The purpose of this experiment was to determine whether preoperative administration of antibiotics and corticosteroids can attenuate the severity of hearing loss (HL) with semicircular canal (SC) transection in a guinea pig model of Pseudomonas aeruginosa (PA) otitis media (OM).

STUDY DESIGN AND SETTING: Prospective and controlled.

METHODS: OM was induced in 64 pigmented guinea pigs by bilateral, transtympanic injection of PA. Two to 4 days later, 1 horizontal SC was randomly transected. In the 1st series, antibiotic therapy was initiated either immediately before or after surgery. In the 2nd series, all animals received preoperative antibiotics, and half received dexamethasone before surgery. Hearing was tested before and after surgery.

RESULTS: PA was recovered in all ears. SC transection was associated with significant HL. HL was better in animals given antibiotics preoperatively (clicks, 16 versus 32 dB, P = 0.0220). Addition of preoperative steroids did not significantly further reduce HL (7 versus 14 dB for clicks, P = 0.6919).

CONCLUSIONS: HL caused by SC transection in PA OM may be attenuated with preoperative antibiotic therapy in the guinea pig.

Histopathologic changes in the middle ear mucosa after exposure to pepsin and unconjugated bile acid

OBJECTIVE

An increasing number of studies indicate that pepsin and bile acid cause damage to the ear, nose, and throat structures as a result of extraesophageal reflux. The aim of this study was to evaluate and compare the damaging effect of bile acids and pepsin on the middle ear mucosa.

MATERIAL AND METHODS

Twenty-nine healthy rats were included in this study. The animals were divided into 5 groups. A single daily dose of 40 μmol/L chenodeoxycholic acid, 40 μg/mL pepsin, and saline were injected separately into the right middle ear of the rats. On day 30, all rats were decapitated, and formalin-fixed, paraffin-embedded samples of the middle ear both from the control and experimental rats were prepared. A semiquantitative analysis was performed.

RESULTS

Inflammatory response was seen in all middle ear mucosa of rats except control group 1. The degree of inflammatory response was higher in the bile acid group when compared with the other groups. Epithelial metaplastic changes with varying number of goblet cells were observed in both the bile acid- and pepsin-injected groups. These metaplastic changes were also higher in the bile acid-induced group than in the pepsin-injected group.

CONCLUSIONS

This is the first study on the middle ear mucosal damage of both pepsin and bile acid. Our results demonstrate that bile acids were associated with more extensive mucosal injury at pH 7 in comparison to pepsin in a rat animal model. Inflammatory response and metaplastic changes may play an important role in the etiology of middle ear pathologies.

Montelukast is as effective as penicillin in treatment of acute otitis media: an experimental rat study

Background

Leukotrienes are the major factors in the formation of edema and mucus, as well as development of tuba Eustachii dysfunction in acute otitis media. We developed an experimental acute suppurative otitis media model and compared the responses of rats to penicillin and combinations of leukotriene antagonist with respect to histopathological observations conducted in early and late phases.

Material/Methods

A total of 83 ears from 56 Wistar rats were used in this study. Pneumococcus suspension was injected trans-tympanically into all rats. Subjects were classified into 4 different groups with 14 rats in each. In Group A, intramuscular penicillin G was injected for a period of 5 days. In Group B, intraperitoneal montelukast was injected for 21 days in addition to penicillin. In Group C, intraperitoneal montelukast isotonic NaCl in Group D was injected into rats for 21 days.

Results

No significant difference was found between the groups, except for mucosal vascularization with respect to mucosal and TM parameters in early phases. Furthermore, considerable deviations were observed for the recuperation of TM and mucosal inflammation for groups in which subjects were injected with montelukast as compared to other groups of the study in the late phases.

Conclusions

When the parameters of inflammation in the rat middle ear were compared with each other, most of these parameters did not show any statistically significant beneficial effects in montelukast and penicillin groups.

Protease inhibitors α1-antitrypsin and ilomastat are not ototoxic in the chinchilla

OBJECTIVES

Proteases of both the serine and the metalloprotease families have been shown to play a role in the pathogenesis of otitis media. Inhibitors of proteases from each of these families have been shown to beneficially impact disease progression in a number of related chronic inflammatory conditions. The purpose of this study was to assess the safety of protease inhibitors when instilled into the middle ear, with a view to their potential use in the treatment of human otitis media.

STUDY DESIGN

Prospective, randomized, controlled trial in the chinchilla model.

METHODS

After completing baseline auditory testing and bilateral transpalatal obstruction of the Eustachian tube, chinchillas received weekly transbullar injections of protease inhibitor (alpha1-antitrypsin, ilomastat, or both), vehicle, or saline. After 1 month, hearing was tested and the animals were sacrificed. Temporal bone histopathologic examination was performed.

RESULTS

All treatment groups demonstrated a statistically insignificant average loss in long-term hearing (0 dB) for all measures using clicks and tones (P >.15 for all conditions). All treatment groups were statistically insignificantly different from one another (P =.5625). Histopathologic examination revealed no significant inner ear changes.

CONCLUSIONS

Protease inhibitors that are currently under study in animal models and humans for the treatment of inflammatory diseases that are related to imbalances between protease and protease inhibitor have no significant toxic effect on the inner ear of chinchillas. These findings support the safety of further clinical trials using these inhibitors to treat middle ear inflammation.

Effect of betamethasone and diclofenac sodium on serum and tissue concentration of amoxicillin. In vivo study in rats

Objective:

Antimicrobial agents in combination with anti-inflammatory drugs have been usually prescribed in both Medicine and Dentistry. However, few scientific reports support this clinical practice. The aim of this study was to evaluate the effect of betamethasone and diclofenac sodium on serum and tissue concentration of amoxicillin in rats.

Methods:

Four polyurethane sponges were implanted in the back skin of 48 rats. After seven days the animals were divided into 6 groups (n=8). Group 1: amoxicillin (25 mg/kg); G2: diclofenac sodium (2.5 mg/kg); G3: betamethasone (0.1 mg/kg); G4: diclofenac sodium and amoxicillin; G5: betamethasone and amoxicillin; and G6: 0.9% sodium chloride solution (1.0 mL - control group). All drugs were administered in a single dose. After 90 minutes, the granulomatous tissues of each animal were surgically removed and weighed. Blood was collected from cervical plexus, centrifuged and 10μL of serum was placed on paper discs. In order to estimate amoxicillin concentration, serum and granulomatous tissues were separately submitted to microbiological assay, which used 10⁸cfu/mL of Staphylococcus aureus ATCC 25923 (penicillin-susceptible strain). After incubation (18 hours, 37°C) the inhibition zones were measured and compared to a regression curve.

Results:

No inhibition zones were observed for groups 2, 3 and 6. Tissue and serum concentrations of both G1 (4.14μg/g and 2.06μg/mL, respectively) and G5 (3.87μg/g and 1.70μg/mL, respectively) showed statistically significant differences (Kruskal-Wallis, p<0.05) in comparison to G4 (1.45μg/g and 0.41μg/mL, respectively). G1 and G5 did not differ significantly (p>0.05).

Conclusion:

Considering single doses, betamethasone did not interfere with amoxicillin levels but diclofenac sodium reduced both tissue and serum levels of amoxicillin in rats.

Effect of pneumococcal vaccination on otitis media with effusion in children older than 1 year

Pneumococcal vaccines may be effective in preventing or decreasing the burden of disease related to otitis media. In study reported here, we investigated the effectiveness of pneumococcal vaccination on otitis media with effusion (OME) in children (n = 383 children aged 1-7 years) with a history of recurrent otitis media within the framework of a randomized double blind placebo controlled trial. Children were randomized to be immunized with either a 7-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide vaccine, or by hepatitis A or B vaccines. The proportion of children diagnosed with OME at the scheduled follow-up visits--7, 14, 20 and 26 months after randomization--was then calculated. OME was diagnosed according to an algorithm combining tympanometry and otoscopy. The percentage of children diagnosed with OME was similar in the pneumococcal vaccination group and control group at both baseline and the follow-up visits at 7, 14, 20 and 26 months--52.9 versus 52.7, 44.9 versus 44.2, 34.9 versus 31.5, 40.8 versus 32.2 and 31.4 versus 26.1, respectively (corresponding to p-values of 0.96, 0.89, 0.51, 0.13 and 0.36, respectively). We conclude that the combined pneumococcal conjugate and the polysaccharide vaccination have no beneficial effect on OME in children aged 1 year or older with a history of recurrent otitis media. Therefore, these vaccinations are not indicated in the prevention of OME in these children.

Dexamethasone does not alter in vitro antibacterial efficacy of gentamicin

OBJECTIVES

Aminoglycoside ototoxicity may be mitigated by administration of dexamethasone; however, dexamethasone could theoretically impair its antibacterial properties. The purpose of this experiment was to determine if dexamethasone decreases the antibacterial activity of gentamicin against Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA).

STUDY DESIGN

In vitro microbiological assay.

METHODS

Four separate trials of minimum inhibitory concentration (MIC) testing were performed for gentamicin against five PA strains and six SA strains, with and without the addition of high and low concentrations of dexamethasone.

RESULTS

MICs were not changed by more than one dilution with the addition of either high or low concentrations of dexamethasone for any of the PA and SA strains.

CONCLUSION

Dexamethasone does not impair the antibacterial efficacy of gentamicin for PA and SA. This supports the role of dexamethasone as an oto-protectant with aminoglycoside therapy.

Alpha1-antitrypsin single dose adjuvant therapy for acute otitis media

OBJECTIVES

Proteases have been shown to play a role in the pathogenesis of otitis media. Inhibition of these proteases can improve treatment outcomes in certain conditions. The goal of this study was to determine if intratympanic administration of a single dose of the protease inhibitor, recombinant alpha 1-antitrypsin (rAAT), can facilitate resolution of acute otitis media (AOM) in the chinchilla.

METHODS AND MEASURES

Pneumococcus was injected into both middle ears of 12 chinchillas. After 3 to 4 days, middle ears were cultured, systemic antibiotics were initiated, and rAAT or its vehicle was administered into the middle ears of all animals. Serial tympanic membrane (TM) scoring, tympanometry, and auditory-evoked brain stem response testing were performed. Animals were sacrificed at varying timepoints and temporal bones studied for objective measures of OM.

RESULTS

Although not reaching statistical significance, there was a trend to more rapid resolution of AOM in rAAT-treated ears. Tympanometry, auditory thresholds, and quantitative histologic parameters did not differ between rAAT and vehicle treated ears.

CONCLUSIONS

A single dose of intratympanic rAAT likely does not facilitate the resolution of antibiotic-treated pneumococcal AOM in the chinchilla model. Serial administration of this protease inhibitor may be necessary to see a significant treatment effect.

Evaluation of the clinical efficacy of Qingqiao Capsule in treating patients with secretory otitis media

OBJECTIVE

To observe the clinical efficacy of Qingqiao Capsule (QQC) in treating patients with secretory otitis media (SOM).

METHODS

A total of 90 patients were randomly assigned into the treated group (n = 45) and the control group (n = 45). Patients in the treated group were administrated with QQC, 5 capsules each time, 3 times a day for totally 10-14 days, and those in the control group were given per os cefaclor capsules 0.5 g each time for adult, 3 times a day, or 20 mg/(kg.d) for children, for 10-14 days. The therapeutic efficacy of treatment on the patients was observed and compared after treatment and followed up for 3-6 months.

RESULTS

(1) The clinical efficacy in the treated group was superior to that in the control group with significant statistical difference (P < 0.01); (2) Comparison of the efficacies in patients of three different TCM syndrome types (the external pathogenic wind invasion caused auditory orifice stuffiness type, the Gan-Dan damp-heat steaming up auditory orifice type and the Pi-deficiency dysfunction induced dirty dampness blocking ear type) showed no statistically significant difference (P > 0.05); (3) The vanishing rate and time needed of the main symptoms and signs in the treated group were superior to those in the control group on ear muffle, tinnitus, hearing impairment, hydrotypanum, pure tone threshold and abnormal tongue figure, and the difference was statistically significant (P < 0.05 or P < 0.01), only those of earache, otopiesis and abnormal pulse figure were insignificantly different between the two groups (P > 0.05).

CONCLUSION

QQC is an effective Chinese composite medicine on patients with SOM, and shows no obvious adverse reaction.

A comparative study of intratympanic steroid and NO synthase inhibitor for treatment of cochlear lateral wall damage due to acute otitis media

We studied the damage to the cochlear lateral wall induced by otitis media and the therapeutic effects of intratympanic administration of steroid and nitric oxide (NO) synthase inhibitor. In Sprague-Dawley rats, right middle ear cavities were inoculated with lipopolysaccharide, followed after 30 min by intratympanic administration of dexamethasone, NOS-inhibitor or PBS. Twenty-four hours after lipopolysaccharide inoculation, cochlear blood flow was measured by laser-Doppler flowmetry. Prostaglandin E(1) was topically applied to the round window membrane of the right ear and changes in cochlear blood flow were calculated. Changes of cochlear blood flow were significantly different among the three groups. Increases in cochlear blood flow following PGE(1) application were higher in the group that received NOS-inhibitor. Electron microscopic examination revealed that changes in the stria vascularis were less severe in rats treated with dexamethasone or NOS-inhibitor. Our results show the effectiveness of intratympanic dexamethasone or NOS-inhibitor in treating cochlear lateral wall damage caused by otitis media.

Topical ciprofloxacin/dexamethasone otic suspension is superior to ofloxacin otic solution in the treatment of children with acute otitis media with otorrhea through tympanostomy tubes

OBJECTIVE

To determine the efficacy and safety of topical ciprofloxacin/dexamethasone otic suspension compared with ofloxacin otic solution in the treatment of acute otitis media with otorrhea through tympanostomy tubes (AOMT) in pediatric patients.

METHODS

This multicenter, prospective, randomized, observer-masked, parallel-group study was conducted at 39 sites in 599 children aged >or=6 months to 12 years with an AOMT episode of <or=3 weeks' duration. The mean age of patients was 2.5 years (standard deviation: 2.37 years). Patients received either ciprofloxacin 0.3%/dexamethasone 0.1% otic suspension 4 drops twice daily for 7 days or ofloxacin 0.3% otic solution 5 drops twice daily for 10 days. Clinical signs and symptoms of AOMT were evaluated at clinic visits on days 1 (baseline), 3 (on therapy), 11 (end of therapy), and 18 (test of cure). A patient diary was used to measure time to cessation of otorrhea. Principal pretherapy pathogens included Streptococcus pneumoniae (16.8%), Staphylococcus aureus (13.0%), Pseudomonas aeruginosa (12.7%), Haemophilus influenzae (12.4%), S epidermidis (10.2%), and Moraxella catarrhalis (4.1%).

RESULTS

Ciprofloxacin/dexamethasone is superior to ofloxacin for clinical cure (90% vs 78%) and microbiologic success (92% vs 81.8%) at the test-of-cure visit, produces fewer treatment failures (4.4% vs 14.1%), and results in a shorter median time to cessation of otorrhea (4 days vs 6 days). Ciprofloxacin/dexamethasone treatment is also superior to improvement in clinical response by visit, absence of otorrhea by visit, and reduction of otorrhea volume by visit. Both topical otic preparations are safe and well tolerated in pediatric patients. No change in speech recognition threshold or decrease in hearing from baseline, based on audiometric testing, was noted with either regimen.

CONCLUSION

Topical ciprofloxacin/dexamethasone treatment is superior to topical ofloxacin in the treatment of AOMT.