Determination of Reactive Oxygen Species in Myringotomized Tympanic Membranes: Effect of Vitamin E Treatment

Effects of Papaverine on Experimentally Induced Myringosclerosis

OBJECTIVE

This study aims to investigate the effects of papaverine on experimentally induced myringosclerosis (MS). MS is characterized by hyaline degeneration and calcification of the lamina propria of the tympanic membrane and can adversely affect hearing function if left untreated. The study examined the potential effects of both systemic and topical applications of papaverine on this process.

MATERIALS AND METHODS

In the study, 20 Wistar albino rats were used. The rats were divided into 4 groups and different treatment methods were applied in each group. In group 1, myringotomy was performed, but no additional intervention was performed. In group 2, saline-impregnated gelfoam was applied after myringotomy. In groups 3 and 4, topical and systemic applications of papaverine hydrochloride were performed. Tympanic membranes were examined under a microscope after 21 days, and the severity of MS and histopathologic changes were evaluated.

RESULTS

The papaverine-treated groups observed a significant increase in otomicroscopic sclerosis, the degree of inflammation, and tympanic membrane thickness. The degree of fibrosis was higher in group 3 compared with the other groups. The results showed that papaverine administration increased the occurrence of MS.

CONCLUSION

This study suggests that papaverine may increase MS through its vasodilating effect. Vasodilation is thought to cause an increase in oxygen-derived free radicals, which may contribute to the pathogenesis of MS. The results suggest that the effects of papaverine on MS should be carefully evaluated.

Evaluation of aortic stiffness by echocardiography in tympanosclerosis patients

BACKGROUND AND AIMS

Tympanosclerosis (TS) is a scarring process that may occur during otitis media. Aortic stiffness (AS) is a significant predictor for the development of heart diseases due to its close relationship with atherosclerosis. Similar pathophysiological processes based on inflammation may explain both TS and AS formation. This study aimed to determine echocardiographically whether aortic elasticity is impaired in TS-detected patients and to correlate blood inflammatory parameters with TS and aortic elasticity.

METHODS

Ninety-eight participants diagnosed with chronic otitis media were enrolled in the study. TS-detected 42 participants were assigned to the study group, while 56 without TS constituted the control group. The two groups' demographic, clinical, echocardiographic, and laboratory characteristics were comparable.

RESULTS

Demographic, clinical, and laboratory parameter differences were insignificant. Hs-CRP, neutrophil-to-lymphocyte ratio, and systemic immune-inflammation index were significantly higher in the study group than in the control group (P=0.018, P=0.003, P=0.019, respectively). The study group had significantly lower aortic strain (11.80 ± 4.84 vs. 16.30 ± 3.91; P<0.001) and distensibility (5.23 ± 2.68 vs. 7.24 ± 2.89; P=0.001) values than the control group. The AS index was significantly higher in the study group than in the control group (4.81 ± 2.41 vs. 3.12 ± 1.02; P<0.001).

CONCLUSION

In TS-detected patients, AS parameters were found to be impaired. Aortic elasticity parameters measured by echocardiography, a non-invasive and easily accessible method, may signify early cardiovascular involvement in TS-developed patients.

Is there any effect of montelukast on prevention of myringosclerosis after myringotomy in a rat model?

OBJECTIVES

In this study, our aim was to identify the possible effects of montelukast sodium (ML) on the prevention of experimentally induced myringosclerosis.

MATERIALS AND METHODS

Twenty-eight female Wistar albino rats were used and they were divided into four groups randomly. Tympanic membranes (TM) of all animals were perforated and then group 1 received no treatment (control group), group 2 was treated with a topical saline solution, group 3 received topically ML and group 4 received orally ML. On the 15th day, all animals were euthanized. Tympanic membranes were evaluated otomicroscopically and histopathologically.

RESULTS

The histopathological findings, compared against a control and saline groups, showed the topically and orally ML groups had statistically significant differences of degree of myringosclerosis (p < 0.002) and median thickness of the TMs (p < 0.001). Suppression of inflammation was statistically significant only in the oral ML treatment group (p < 0.002).

CONCLUSION

Oral and topically administration of ML reduced myringosclerosis formation in myringotomies rats.

Effect of Topical Dexamethasone for Preventing Experimentally Induced Myringosclerosis

Objective

We aimed to examine the effect of topical dexamethasone by otomicroscopic and histologic examinations for preventing myringosclerosis induced by myringotomy in rat tympanic membranes.

Methods

Twenty-one Sprague Dawley rats (42 ears) were randomly divided into the following three groups after otomicroscopic examinations: experimental surgical group (5 rats), control group (8 rats), and study group (8 rats). The rats of all the groups underwent myringotomy in both tympanic membranes. Other than myringotomy, no additional procedure was performed for the rats in the experimental surgical group. In the control group, 0.9% NaCl was applied to the ears, whereas in the study groups, topical dexamethasone was applied to the ears. These applications in the control and study groups were repeated for nine days. On the 10th day of the study, the rat ears of all groups underwent otomicroscopic and histologic examinations. The prevalence and process of myringosclerosis were evaluated by otomicroscopic examination, whereas inflammation, membrane thickness, and myringosclerosis intensity were evaluated by histologic examination.

Results

The growth of myringosclerosis with otomicroscopic examination was lesser in the study group in which topical dexamethasone was applied than the control and the experimental surgical groups. Moreover, it was observed that myringosclerosis effected fewer quadrants in the study group.Histologic examinations revealed that inflammation was significantly lesser in the study group than in the experimental surgical and control groups. The average membrane thickness values were significantly lesser in the study group than in the experimental surgical group. With respect to myringosclerosis growth, no statistically significant difference was observed among all groups, whereas with respect to myringosclerosis intensity, the rat ears in the study group were less severely affected.

Conclusion

Thus, our study results suggest that applying topical dexamethasone after myringotomy has positive effects on limiting the intensity and prevalence of myringosclerosis.

Do all antioxidant supplements have the same potential effect on preventing myringosclerosis?

Objectives

Myringosclerosis is an irreversible pathological healing mechanism of the tympanic membrane which can result in the formation of sclerotic plaques. Antioxidant treatment is a recognised prevention therapy and coenzyme Q10 (CoQ10), lycopene, and grape seed extract (GSE), were used in this manner.

Methods

Forty-four Wistar rats were used in this experiment, and, following myringotomies, the animals were randomly divided into four groups. CoQ10, lycopene or GSE was administered orally to the respective groups, starting from the day of surgery. Otomicroscopy examination was performed on the 14th day. All tympanic membrane lesions were evaluated and compared otomicroscopically and histopathologically.

Results

The otomicroscopy and histopathological findings, compared against a control (saline) group, showed the CoQ10, lycopene, and GSE groups had statistically significant differences of degree of sclerosis (P<0.001).

Conclusion

CoQ10, lycopene, and GSE were compared against a saline group and their antioxidative and anti-inflammatory effects were similar. The formation of myringosclerotic plagues after experimental myringotomy in rats significantly decreased and diminished after systemic administration of the three different antioxidant supplements.

The effect of lycopene on experimental myringosclerosis

OBJECTIVES

The aim of this study was to investigate the effect of lycopene on myringosclerosis development using histopathological and immunohistochemical analyses.

METHODS

Fifty-six intact tympanic membranes of 28 guinea pigs were included in the study. Subjects were randomly divided into four groups (n=7/group). Group I (control group) did not receive any treatment after myringotomy. Group II (lycopene treatment after myringotomy) received oral lycopene (once daily at the same time, 10mg/kg, dissolved in water, administered with a catheter). The treatment lasted seven days. Group III (lycopene treatment before and after myringotomy), received lycopene treatment (same dose and route of administration) for seven days. Myringotomy was performed on day 8, and lycopene treatment was initiated immediately, and continued for seven days (same dose and route of administration). Group IV (lycopene treatment before myringotomy) received lycopene treatment one week before myringotomy using the same method and dose for seven days. Myringotomy was performed on day 8. Lycopene was not administered after myringotomy. Fourteen days after myringotomy, myringosclerosis was evaluated automicroscopically and scored. Following decapitation, bulla were removed and immersed in a 10% formaldehyde solution. Sections were cut for histopathological and immunohistochemical examination, and thickness, sclerosis, inflammation, and collagen-IV accumulation were scored semi-quantitatively.

RESULTS

In the present study, the level of myringosclerosis was significantly lower in lycopene-treated groups compared to the control group (p<0.05). In addition, thickness, inflammation, sclerosis, and collagen-IV accumulation were significantly lower in the lycopene-treated groups compared to the control group (p<0.05). The timing of lycopene administration - i.e. before and/or after surgery - did not cause any difference with respect to myringosclerosis development.

CONCLUSION

Lycopene, a strong antioxidant, may represent a good alternative treatment to prevent the development of myringosclerosis.

Pomegranate extract: a potential protector against aminoglycoside ototoxicity

OBJECTIVE

To investigate the effectiveness of pomegranate extract as protection against aminoglycoside ototoxicity.

DESIGN

Prospective, randomised, controlled, experimental study.

SUBJECTS

Eighteen Wistar albino rats were randomly allocated to 5 days of either: saline injections; gentamicin injections; or pomegranate extract (100 µl/day via gavage) plus gentamicin injections. Distortion product otoacoustic emissions were tested before treatment and on day 3. After treatment, reactive oxygen species levels were measured in each rat's right cochlea and right kidney via chemiluminescence.

RESULTS

Baseline emission amplitudes were similar. Post-treatment emissions differed significantly in the two treatment groups (p < 0.001). Cochlear reactive oxygen species levels were significantly higher in the gentamicin group (mean ± standard deviation, 316.6 ± 36.5 relative light units per mg) than the gentamicin plus pomegranate extract group (240 ± 24.6 relative light units per mg) (p = 0.004); control group levels were 119.1 ± 10.3 relative light units per mg. Renal reactive oxygen species levels were similar for the control and gentamicin plus pomegranate extract groups (p = 0.59) but much higher in the gentamicin group (p = 0.004).

CONCLUSION

Concurrent systemic pomegranate extract administration reduced reactive oxygen species level increases and otoacoustic emission changes, following aminoglycoside injection.

Is there any effect of coenzyme Q10 on prevention of myringosclerosis? Experimental study with rats

Objective

Method

Results

Conclusion

Levels of reactive oxygen species in rat tympanic membranes after incisional versus radiofrequency myringotomy

OBJECTIVE

A close relationship between reactive oxygen species (ROS) and myringosclerosis, which is a common complication of myringotomy, was recently reported. The objective of this study was to measure ROS levels directly in rat tympanic membranes using luminol-aided chemiluminescence (CL) in order to compare the levels of ROS after incisional and radiofrequency (RF) myringotomy.

METHODS

Fifteen Sprague-Dawley rats were separated into three groups of five animals each. Bilateral myringotomies were made using an appropriate myringotomy lancet in Group 1 and RF in Group 2. Group 3 served as the control group with no myringotomy. Twenty-four hours after the procedure, all tympanic membranes were inspected with an otomicroscope and then excised for the measurement of ROS using luminol-aided CL.

RESULTS

The mean ROS level in Group 1 was significantly higher than that in Groups 2 and 3 (p<0.05 for both). The difference in mean ROS level between Groups 2 and 3 was not significant (p>0.05). Otomicroscopy revealed increased vascularity and vessel dilation in all tympanic membranes that underwent myringotomy. Vascular dilation was observed in the annular region in the vessels that passed along the long arm of the malleus, in addition to the vessels feeding the anterior and posterior tympanomalleolar folds.

CONCLUSIONS

Although the relationship between ROS and the development of myringosclerosis after myringotomy has been demonstrated, the present study is the first to compare incisional and RF myringotomy based on the measurement of ROS levels. Our results indicate that the increase in ROS due to myringotomy was greater following incisional myringotomy than RF myringotomy.

The preventive effect of N-nitro L-arginine methyl ester in experimentally induced myringosclerosis

OBJECTIVE

The purpose of this study was to investigate the antiinflammatory and antifibrotic effects of N-nitro L-arginine methyl ester (L-name) in experimentally induced myringosclerosis.

METHODS

Twenty Wistar albino rats were bilaterally myringotomized and divided randomly into four groups, each including five rats. Group I received no treatment, Group II was treated with topical saline solution, Group III received topical L-NAME and Group IV received intraperitoneally administered L-NAME. After 2 weeks, the tympanic membranes were examined and scored by otomicroscopy regarding the extent of the myringosclerosis. Then the tympanic membranes were harvested and evaluated histopathologically by light microscopy. The intensity of inflammation and degree of myringosclerosis were evaluated, the mean thickness of tympanic membranes were also measured.

RESULTS

The tympanic membranes of Groups I and II showed extensive myringosclerosis in contrast to those of Groups III and IV which had significantly less or no changes (p < 0.05). The inflammation and fibroblastic activity of the lamina propria in the tympanic membranes of Groups III and IV were found to be significantly less pronounced (p < 0.05). The tympanic membranes were found to be significantly thicker in Groups I and II when compared with Groups III and IV (p < 0.05).

CONCLUSION

Our results showed that both topical and intraperitoneal applications of L-NAME supressed inflammation, reduced fibroblastic proliferation and decreased the formation of myringosclerosis in myringotomized rat tympanic membranes.

Antioxidant effect of pomegranate extract in reducing acute inflammation due to myringotomy

OBJECTIVE

To assess the effect of pomegranate extract on acute inflammation due to myringotomy.

DESIGN

Prospective, randomised study.

SUBJECTS

Thirty Sprague-Dawley rats were divided into three groups. Group one constituted controls. Group two underwent myringotomy. Group three underwent myringotomy and also received 100 µl/day pomegranate extract, via gavage, one day before and two days after surgery. Following sacrifice 48 hours after myringotomy, the animals' right ears were used to determine the concentration of reactive oxygen species, using the chemiluminescence method; left ears were used for histological study.

RESULTS

Reactive oxygen species levels were significantly decreased in group three compared with group two (p < 0.01). The density of inflammatory cells in group three was significantly less than that in group two (p < 0.01). Lamina propria thickness and vessel density were also significantly decreased in group three compared with group two (p < 0.01).

CONCLUSION

Our results indicate that oral pomegranate extract decreases reactive oxygen species concentration and acute inflammation in the tympanic membrane after myringotomy.

Resonance Raman spectroscopy as an effective tool for the determination of antioxidative stability of cosmetic formulations

Carotenoids beta-carotene, lutein, lycopene and others are well-known powerful antioxidants acting as an effective neutralizer of free radicals produced in the human organism as a result of the influence of stress factors, such as UV irradiation. The protective effect of antioxidants is used in cosmetic products to increase the skin protection against the destructive action of free radicals and for the stabilization of formulations against oxidation. In the skin, the different antioxidant substances form protection chains to avoid their destruction by the interaction with the free radicals. Similar effects have to be expected also in topically applied formulations. In the present study the influence of different mixtures of antioxidants (beta-carotene, vitamins C and E) on the stability of antioxidants in formulations used for skin treatment was investigated. The measurements were carried out by using non-invasive resonance Raman spectroscopy for the detection of the carotenoid concentration in the cosmetic formulations.

Ginkgo biloba, a free oxygen radical scavenger, affects inflammatory mediators to diminish the occurrence of experimental myringosclerosis

CONCLUSION

Systemic Ginkgo biloba extract treatment reduces the levels of nitrite/nitrate, malondialdehyde, and superoxide dismutase and increases the levels of glutathione peroxidase. By scavenging free oxygen radicals, ginkgo extract prevents the formation of myringosclerosis.

OBJECTIVE

Our objective was to evaluate inflammatory mediators to determine the antioxidant and anti-inflammatory effect of Ginkgo biloba extract to diminish myringosclerosis.

MATERIALS AND METHODS

Thirty Wistar Albino rats, weighing 320-400 g were used. The upper posterior quadrants of both tympanic membranes were myringotomized and divided into four groups. Ginkgo biloba extract was given orally to groups 1 and 2 comprising eight rats with doses of 100 mg/kg/day and 200 mg/kg/day, respectively. Seven rats in group 3 received 1.5 ml/day saline and seven rats were left untreated. After 10 days of treatment, otomicroscopic evaluation of tympanic membranes and measurement of anti-inflammatory mediators such as superoxide dismutase, nitrite/nitrate, glutathione peroxidase and malondialdehyde were performed.

RESULTS

Myringosclerosis was significantly more severe in control and saline groups than in Ginkgo biloba groups. The levels of nitrite in ginkgo-treated groups were significantly lower than in untreated and saline-treated groups, while glutathione peroxidase levels were significantly higher. The levels of malondialdehyde and superoxide dismutase were lower in ginkgo groups but not significantly.

Evaluation of the polymorphism in the Toll-like receptor 4 (TLR4) genes of tympanosclerosis patients

OBJECTIVE

Although eardrum perforations which endure etiopathogenesis for a long-time and middle ear infections are proposed for causing the tympanosclerosis (TS), tympanosclerosis emerges in some chronic otitis media (COM), some of them do not appear although a continuing COM and enduring perforation last. In this study, the effect of the molecular reasons which display genetic differences in TS formation is evaluated; our aim is to determine the Asp299Gly polymorphism frequencies in the TLR4 gene of patients with TS who have COM, and patients who do not.

MATERIALS AND METHODS

Patients who have undergone COM surgery, were divided into two groups of 50 persons who were selected in accordance with the fact, whether they had TS in their middle ear cavity or not during operation. 100 healthy persons who had similar demographic data, were evaluated as the control group. The DNA isolation was executed by using standard methods with peripheric blood specimen of the diseased group and control group. The Restriction Fragment Length Polymorphism method was used in determining the Asp299Gly allel in the TLR4 gene. Items of 249 bc for the wild tip (Asp) post-restriction enzyme segment wild tip (Asp) allel, and 23 bc and 196 bc post-restriction enzyme segment polymorphic allel (Gly) were obtained.

RESULTS

TLR4 Asp299Gly polymorphism (10%) was asserted in a total of five specimens in the diseased group with TS. TLR4 Asp299Gly polymorphism was found positive in only one (2%) of the 50 phenomenons in the group without TS. TLR4 Asp299Gly polymorphism was found positive in six (6%) of the 100 phenomenons in the control group. The positive polymorphism in phenomenons with TS was significant in accordance with statistics, when compared with the group without TS (p<0.05). However, although the polymorphism rates were higher than the rates of the control group, it was not statistically significant (p>0.05).

CONCLUSION

TS may not appear in many patients who had undergone middle ear infection, and had perforation for many years. The polymorphism in arteriosclerosis in the TLR4 gene which caused the inflammatory cytokines oscillation recognize the bacterial LPS, was also accused. It is engrossing to find out from the results of our study on a restricted number of patients, and on only one gene, that molecular reasons which display genetic differences can also be effective in forming TS. Serial researches of greater dimensions are required.

The preventive effect of ginkgo biloba extract in myringosclerosis: study in rats

OBJECTIVE

To determine the preventive effect of Ginkgo biloba extract in the formation of myringosclerosis.

STUDY DESIGN

Prospective, randomized clinical study.

MATERIALS AND METHODS

Posterosuperior quadrant of tympanic membranes of twenty-five Wistar Albino rats were bilaterally myringotomized. They were divided into three groups randomly. Groups 1 and 2 were administered 100 mg/kg/day and 200 mg/kg/day systemic Ginkgo biloba extract. The third group was treated with 1 mL/day saline solution. After 10 days of treatment, myringotomized membranes were examined by otomicroscopy and harvested. They were evaluated histopathologically by light microscopy and compared according to the occurrence of myringosclerotic plaques and the thickness of membranes.

RESULTS

Tympanic membranes of groups 1 and 2 nearly had no existence of myringosclerosis (72.2% in group 1 and 83.3% in group 2, P = 0.434). However, in group 3, only 14.3 percent had no myringosclerosis (P < 0.001). Thickness of membranes in group 1 was 0.13 +/- 0.25, group 2 was 0.06 +/- 0.02, and group 3 was 0.19 +/- 0.35 mm. Group 3 had significantly thicker membranes compared with groups 1 and 2 (P < 0.001 for group 2 and P = 0.003 for group 1).

CONCLUSION

Formation of experimental myringosclerosis was reduced or inhibited and tympanic membranes were thinner after systemic Ginkgo biloba extract administration.

The effect of Vitamin E treatment on the development of myringosclerosis after ventilation tube insertion

OBJECTIVES

Recent studies have established the relationship between the reactive oxygen species and myringosclerosis. Furthermore several antioxidants have been known to prevent myringosclerosis. All the previous studies supporting this hypothesis have been performed on animals. The aim of our study is to investigate the possible effect of Vitamin E on the development of tympanosclerosis after VT insertion on human subjects.

METHODS

72 children undergoing myringotomy and VT insertion were included in the study. Vitamin E was applied to the right ear and no treatment was applied to the left ear. Both ears were examined at the end of 9 months with otomicroscopy. Myringosclerosis formation at the end of the study period was noted for each ear.

RESULTS

Myringosclerosis was found in 33 of the 144 ears. The overall incidence was 22.9%. While 22 (30.6%) of the 72 left ears showed myringosclerosis otomicroscopically, in only 11 (15.3%) of the 72 right ears that were treated with Vitamin E was myringosclerosis observed at the end of the study period. Of these nine cases were bilateral.

CONCLUSION

Animal studies have well documented the development of myringosclerosis after myringotomy and VT insertion and beneficial effects of different antioxidants. Our study has shown similar results in human subjects. Further clinical studies consisting of a larger patient population are needed to bring about routine clinical use of antioxidants in myringotomy and VT insertion.

Vitamin e-coated tympanostomy tube insertion decreases the quantity of free radicals in tympanic membrane

OBJECTIVE

Tympanosclerosis is a common sequela of ventilation tube treatment of otitis media with effusion causing hearing disability. It is associated with an increased production of free radicals (also known as reactive oxygen species) after myringotomy. Vitamin E is a scavenger of different free radicals by working as an antioxidant. The aim of the present study was to evaluate the effect of vitamin E-coated tympanostomy tube insertion at quantity of free radicals in rat tympanic membrane.

METHODS

This prospective, controlled animal study consisted of male Sprague-Dawley rats divided into two groups of 10 animals each. Ordinary silcone tubes were applied to the right ears of the first group and vitamin E-coated silcone tubes were applied to the right ears of the second group. The left ears were used as controls. Then, the animals were killed and chemiluminescence measurements were made for tympanic membranes.

RESULTS

Reactive oxygen species levels (ROS) were significantly increased in right ears of the first group when compared with the control ears (P < .0001), and the levels were statistically significant decreased in right ears of the second group as compared with the operated ears of the first group (P < .0001). The free radical levels of right and left ears in the second group were similar.

CONCLUSIONS

Our results indicate that vitamin E-coated tube insertion decreases the quantity of reactive oxygen species in tympanic membrane after myringotomy and tympanostomy tube insertion.