The effectiveness of berberine on noise-induced hearing loss: a rat model

SUMMARY OBJECTIVE: Noise-induced hearing loss is a preventable form of hearing loss that has serious social and economic impacts. This study aimed to investigate the protective effect of berberine, a potent antioxidant and anti-inflammatory agent, against Noise-induced hearing loss. METHODS: After applying distortion product otoacoustic emission, 28 female Sprague-Dawley rats were randomly divided into four groups. Group 1 was designated as acoustic trauma group, and rats in this group were exposed to white noise for 12 h at an intensity of 4 kHz 110 dB sound pressure level. Group 2 was the control group. Group 3 was designated as the berberine group, and 100 mg/kg of berberine was administered to rats in this group by intragastric lavage for five consecutive days. Group 4 was designated as the acoustic trauma+berberine group. distortion product otoacoustic emission was repeated on the 6th day of the study and cochlear tissues of rats were dissected for histopathological and immunohistochemical analyses after sacrificing rats. RESULTS: The distortion product otoacoustic emission results showed a significant decrease in signal-noise ratio values at higher frequencies in rats of the trauma group compared to those in other groups. Acoustic trauma caused severe histopathological impairment at cochlear structures together with severe 8-hydroxy-2-deoxyguanosine expression. Rats in the acoustic trauma+berberine group showed mild histopathological changes with mild 8-hydroxy-2-deoxyguanosine expression and better signal-noise ratio values. CONCLUSION: The histopathological and audiological findings of this experimental study showed that berberine provides protection in Noise-induced hearing loss and may have the potential for use in acoustic trauma-related hearing losses.

A review on medicinal plants used for treating ototoxicity and acoustic trauma induced hearing loss

Hearing loss induced by chemotherapy and acoustic trauma is mainly associated with two factors, free radical formation and apoptosis pathway activation. Despite numerous efforts on reducing the effects of these factors, no definite strategy is still determined to interfere with and control these processes. In recent studies, various protective agents, including antioxidants have been used on animal models, to inhibit the formation of free radicals thus improving hearing loss.In this review article we will discuss the role of traditional herbal medicine in treatment of noise/drug induced hearing loss, focusing on medicinal plants' active substances,as well as their mechanisms of action in reducing or preventing the formation of free radicals thus increasing the rate of survival of cochlea cells. Data have been gathered since year 2000, from scientific publications including the following keywords: deafness, drug toxicity, acute trauma, medicinal herbs and oxidative stress. The study includes all herbs and medicinal plants that have been experimentally used in studies on animal models and clinical trials. The results from these studies indicate the effectiveness of most of these herbs and their active substances through their antioxidative properties. Medicinal plants reported in this review can thus be considered as effective remedies intreating noise/drug induced hearing loss,yet further studies need to be done.

Impacto bio-psico-social del uso indiscriminado de dispositivos de audio / Bio-Psycho-social impact of the indiscriminate use of audio devices

La sociedad del siglo XXI se caracteriza por un gran desarrollo de la ciencia y las tecnologías y, esto entre otras causas, ha generado un uso indiscriminado de dispositivos de audio que a su vez traen consigo contaminación sonora y repercusiones negativas en la salud del hombre. El objetivo general de esta investigación fue determinar la discapacidad auditiva producida por el uso de dispositivos de audio, entre jóvenes y adolescentes. Se realizó estudio observacional, descriptivo y prospectivo de los pacientes con sintomatología audiológica, que asistieron a las consultas de Otocirugía y Audiología del Hospital Faustino Pérez de Matanzas, entre enero del 2014 a febrero del 2015, y que cumplieron los criterios de inclusión, exclusión y salida, además de ajustarse a las consideraciones éticas sobre el tipo de estudio. Se midieron las variables: clínico epidemiológicas, tiempo de uso del dispositivo, grado de lesión, síntomas audiológicos y subjetivos asociados. El grupo más afectado fue el de 20 a 24 años. Los audífonos pequeños generaron mayor daño auditivo, así como la exposición al ruido durante más de 60 min de forma continua y a altas intensidades. Síntomas de la esfera psicoafectiva como la irritabilidad y el insomnio se expresaron con elevada incidencia. Después de ser diagnosticados y tratados, las secuelas audiológicas persistieron necesitando, en algunos casos, la rehabilitación protésica. La educación otoaudiológica es un pilar indispensable en la prevención del trauma acústico inducido por ruidos. Se ofertaron plegables educativos para generalizar los resultados en el nivel primario de atención.

The XXI century society is characterized by a great development of sciences and technologies and this, among other things, has generated an indiscriminate use of audio devices bringing with them a sound contamination and negative repercussion on people´s health. The general aim of this research was determining the hearing disability due to the use of audio devices by young people and teenagers. We carried out a prospective, descriptive, observational study of the patients with audiological symptomatology who assisted the Otosurgery and Audiology consultations of the Hospital Faustino Perez of Matanzas, in the period from january 2014 to february 2015 and fulfilled the inclusion, exclusion and exit criteria, and also adjusted to ethical considerations on the kind of study. The easured variables were: the clinical-epidemiological ones, time of device use, lesion level, associated audiological and subjective symptoms. The most affected age group was the 20-24 years one. The small audiphones are the ones generating more auditory damage, and also the exposition to noise during more than 60 minutes, in a continuous form and at high intensities. There they were appreciated symptoms of the psycho-affective sphere like irritability and insomnia expressed with a high incidence. After being diagnosed and treated, audiological sequels persisted, needing, in some cases, prosthetic rehabilitation. Oto-audiological education is an unavoidable pillar in preventing the noise-induced acoustical trauma. Educative leaflets were given to generalize the outcomes at the primary health care level.

Influence of the 3.0T magnetic resonance on the hearing of newborn infants / 中华实用儿科临床杂志

Objective To evaluate whether or not the 3.0T magnetic resonance (MR) scanner noise has adverse influence on neonatal hearing by using brainstem auditory evoked potentials(BAEP).Methods Forty-nine inpatients who received the MR examination were enrolled in this study from Aug.to Dec.2013,admitted to the Bayi Children's Hospital Affiliated to Beijing Military General Hospital.The Ⅰ,Ⅲ,Ⅴ wave latencies and the inter-peak intervals before and after the MR scan were compared by using SPSS 16.0 software.Results The BAEP results before and after MR examination respectively:(1) The latencies were:left ear Ⅰ wave (1.96 ± 0.22) ms vs (1.95 ± 0.30) ms,right ear Ⅰ wave (1.96 ± 0.22) ms vs (1.97 ± 0.27) ms,respectively; left ear Ⅲ wave (4.79 ± 0.23) ms vs (4.85 ± 0.28) ms,right earlllwave(4.78 ±0.24) ms vs (4.77 ±0.31) ms,respectively;left ear Ⅴ wave (7.10 ±0.24) ms vs (7.12 ±0.33) ms,right ear Ⅴ wave (6.76 ±0.32) ms vs (7.04 ±0.39) ms,respectively(allP ＞0.05).(2) The inter-peak intervals were:left ear Ⅰ-Ⅲ inter-peak interval (2.83 ± 0.23) ms vs (2.86 ± 0.27) ms,right ear Ⅰ-Ⅲ inter-peak interval (2.82 ± 0.24) ms vs (2.80 ± 0.17) ms,respectively ; left ear Ⅲ-Ⅴ inter-peak interval (2.31 ±0.28) ms vs (2.31 ±0.29) ms,right ear Ⅲ-Ⅴ inter-peak interval (2.26 ±0.27) ms vs (2.26 ±0.23) ms,respectively;left ear Ⅰ-Ⅴ inter-peak interval (5.11 ±0.40) ms vs (5.13 ±0.35) ms,right ear Ⅰ-Ⅴ inter-peak interval (5.07 ± 0.39) ms vs (5.07 ± 0.36) ms,respectively(all P ＞ 0.05).Conclusion The 3.0T MR may have no adverse influence on neonatal BAEP.

A Study on the Effectiveness of Treatment of Acoustic Trauma Caused by Gunshot Noise / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The effectiveness of many treatment regimens on acoustic trauma has been debated, but there is no established treatment yet. The purpose of this study was to evaluate the efficacy of steroid treatment in acoustic trauma caused by rifles and to find a critical time limit for the treatment to be effective. SUBJECTS AND METHOD: A retrospective review was conducted for 86 conscripted policemen (97 ears) who suffered acoustic trauma after rifle exercise. Pure tone audiograms were compared before and after treatment at 0.5, 1 and 2 kHz (speech-frequency pure tone average, speech-PTA) and at 4, 6 and 8 kHz (high tone pure tone average, high-PTA). Treatment consisted of drugs (steroid, ascorbic acid, gingko biloba, dextran) and carbogen therapy. The patients who came to the hospital after the first 14 days following injury were grouped as control. Hearing outcomes of patients treated within 3 days and within 7 days were compared to the control. Pre-and post-treatment hearing was compared according to the elapsed time before treatment. RESULTS: Hearing outcomes of patients who received treatment within 3 days of acoustic trauma was better than the control group. Speech-frequency did not show any difference. Treatment within 7 days showed no statistical difference compared to the control. Hearing gain was better when treated within 7 days, especially if it was within 3 days. Speech-frequency showed significant spontaneous recovery within 3 days. CONCLUSION: Our data showed a possible effectiveness of treatment of acoustic trauma on the recovery of high frequency hearing when started within 3 days. Speech-frequency seems to recover spontaneously within 3 days.

Sensorineural hearing loss in high school teenagers in Mexico City and its relationship with recreational noise / Las alteraciones auditivas de escolares adolescentes en la Ciudad de México pueden estar relacionadas al ruido recreativo

The aim of this study was to measure the frequency of hearing loss in a sample of typical public high-school students exposed to recreational noise, and determine associated risk factors. The sample was made up of 214 teenagers from a high-school in Mexico City; subjects were selected randomly per strata. We applied a questionnaire to identify risk factors for hearing loss and performed a battery of audiologic tests consisting of otoscopy, tympanometry, and pure-tone audiometry. The mean age of the sample was 16 ± 1.07 years; 73 percent were male and 27 percent, female. Hearing loss was found in 21 percent of students. The main hearing loss-related risk factor was exposure to recreational noise: frequent attendance at discotheques and pop-music concerts; use of personal stereos; and noise exposure in school workshops. The high frequency of hearing loss in high school students from one Mexico City school (nearly one fifth of the sample) was found to be related to noise exposure mainly during recreational activities.

El objetivo de este estudio fue medir la frecuencia de alteraciones auditivas en una muestra de escolares de educación media superior expuestos a ruido recreativo y determinar algunos factores de riesgo asociados. La muestra estuvo constituida por 214 adolescentes de una escuela de la Ciudad de México. Los sujetos fueron seleccionados al azar por medio de una computadora. Se aplicaron cuestionarios con el objeto de identificar los factores de riesgo para alteraciones auditivas y se les practicaron diversos estudios audiológicos consistentes en: otoscopía, timpanometría y una audiometría a tonos puros. La edad media de la muestra fue de 16 ± 1,07 años, 73 por ciento fueron del sexo masculino y 27 por ciento femenino. Se encontraron alteraciones auditivas en 21 por ciento de los estudiantes. Los principales factores de riesgo asociados a alteraciones auditivas fueron: exposición al ruido recreativo al asistir a discotecas, conciertos de música popular, el uso de equipos de sonido personales y la exposición al ruido en los talleres escolares. Se halló una alta frecuencia (casi una quinta parte) de alteraciones auditivas en alumnos de educación media superior asociada a la presencia de ruido recreativo excesivo.

Brainstem evoked response in bus drivers with noise-induced hearing loss / Audiometria de tronco encefálico em motoristas de ônibus com perda auditiva induzida pelo ruído

Studies carried out by Brainstem Evoked Auditory Potentials (BEAP) in Noise-Induced Hearing Loss (NIHL) workers show different results in relation to neuronal involvement, not involving bus drivers as study object. AIM: to use BEAP in a prospective case/control clinical study to check whether or not there is neural auditory pathway involvement in bus drivers with NIHL. MATERIALS AND METHODS: we selected 50 bus drivers between 27 and 40 years with mild to moderate NIHL, and 20 individuals between 29 and 40 years with normal hearing and without prior history of noise exposure. BEAP tests were carried out and the traces were analyzed. RESULTS: in the NIHL group, the auditory thresholds in 3, 4 and 6 kHz were significantly higher in the left ear. In the NIHL group, potentials PI, PIII and/or PV were not present in a small number of the individuals; we observed a statistically significant increase in PI, PIII and PV absolute latencies, (LIP) LIP I-III interpeak latencies, bilaterally and LIP I-V in the left ear. CONCLUSION: in the NIHL group, besides sensorial injury, changes in BEAP latencies suggest an early functional injury of the first auditory pathway afferent neuron.

Estudos realizados com os Potenciais Auditivos Evocados de Tronco Encefálico (PEATE) em trabalhadores com Perda Auditiva Induzida pelo Ruído (PAIR) apresentam resultados díspares em relação ao comprometimento neuronal, além de não contemplar motoristas de ônibus como objeto de estudo. OBJETIVO: Avaliar pelo PEATE, em estudo clínico de série caso/controle, prospectivo, se há comprometimento das vias auditivas neurais em motoristas de ônibus com PAIR. MATERIAL E MÉTODO: Foram selecionados 50 motoristas de ônibus entre 27 e 40 anos portadores de PAIR leve a moderada; e 20 sujeitos entre 29 e 40 anos com audibilidade normal e sem antecedentes de exposição a ruído. Os PEATEs foram realizados e os traçados analisados. RESULTADOS: No grupo PAIR, os limiares auditivos em 3, 4 e 6 kHz foram significativamente maiores na orelha esquerda. No grupo PAIR, os potenciais PI, PIII e/ou PV foram ausentes em uma pequena parcela; foi observado prolongamento estatisticamente significante das latências absolutas de PI, PIII e PV, das latências interpicos (LIP) LIP I-III, bilateralmente e da LIP I-V na orelha esquerda. CONCLUSÃO: No grupo PAIR, além da lesão sensorial, as modificações das latências do PEATE sugerem lesão funcional do primeiro neurônio aferente da via auditiva, de forma precoce.

Occurrence and Persistence of Tinnitus after Acute Acoustic Trauma by Gunshot / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Acute acoustic trauma (AAT) by gunshot can be the cause of hearing loss and tinnitus. Tinnitus after AAT frequently disappears with time. But the prognosis of this injury is very difficult to predict. This study tried to identify the factors influencing on tinnitus to occur and persist after AAT. SUBJECTS AND METHOD: A group of 268 military subjects who get the gunshot training with K-2 rifle once after conscripted was asked to answer the questions: age, otologic history, number of firing, usage of earplugs, presence of tinnitus after gunshot and its characteristics, relapsed time after firing, Tinnitus Severity Index (TSI) questionnaire. Physical examination and pure tone audiometry were conducted to the subjects with existing tinnitus on the questionnaire. RESULTS: 95 patients (36.4%) experienced tinnitus immediate after gunshot among 261 subjects. It is obvious that wearing earplugs could prevent immediate tinnitus after AAT. There was statistical significance between tinnitus with earplug and without it (p=0.000). At the time of questionnaire, 27 (10.3%) were complaining of tinnitus. Among factors such as age, number of firing, wearing earplugs, severity of tinnitus and relapsed time after firing, only severity of tinnitus has the significant effect with the persistence of tinnitus (p=0.046). CONCLUSION: Wearing earplugs can prevent tinnitus immediately after AAT, but does not seem to be the factor decreasing the prevalence of tinnitus. It was the only factor related to severity of tinnitus and to existing tinnitus.

Niveles de intensidad de la música durante un torneo de resistencia aeróbica en Costa Rica / Music intensity levels during an aerobics endurance tournament in Costa Rica

El propósito del presente artículo es describir los niveles de ruido generados en una competencia de resistencia aeróbica y se analizan las posibles implicaciones para la salud de la contaminación por ruido. La danza aeróbica es un modo de ejercicio que se ha extendido por todo el mundo, con el fin de posibilitar la práctica de una actividad física que combina música y movimiento. Al incluir el elemento musical en las clases de danza aeróbica, se expone a las personas que practican esta modalidad, al ruido que provoca un alto volumen. Hay investigadores que se han dedicado a estudiar la incidencia del ruido, a indicar los rangos permitidos en lugares de entretenimiento y los gimnasios e informar sobre el peligro de perder momentánea o permanentemente el sentido auditivo al exponerse continuamente a ambientes ruidosos. La presente investigación se realizó en las instalaciones deportivas de la Universidad de Costa Rica, durante un torneo de resistencia aeróbica. Se utilizó un medidor del nivel de sonido marca RadioShack, cat. No. 33-2055. Se encontró que los niveles de sonido utilizados para esta competencia excedieron los 90dB permitidos, ya que oscilaron entre 101 y 119 dB, durante los 120 minutos de duración de la actividad. Se requiere de mayor investigación en esta área en Costa Rica y ejercer un sistema de vigilancia para la contaminación sónica en los gimnasios.

The purpose of the study was to describe noise levels during an aerobics tournament and the potential health implications of noise contamination. Aerobic dance is a worldwide known exercise mode that allows people to practice a physical activity that combines both, music and movement. When music is used in aerobic dance classes people are constantly exposed to the noise produced by high volume of the music. Researchers have studied the incidence of noise to indicate the range of noise permitted in entertainment facilities and fitness centers, and to inform to the population about the hazards of short- and long-term noise exposure on hearing loss. This study took place at the sport facilities of the University of Costa Rica during an aerobics endurance tournament. A RadioShack® (cat. N° 33-2055) noise meter was used to measure noise levels. We found that sound levels for this competition exceeded the permitted 90dB, since these values ranged from 101 to 119 dB during the 120 min duration of the activity. More research in this area is necessary as well as a surveillance system for noise contamination in fitness facilities.

Prognostic Factors of Acute Acoustic Trauma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The prognosis and prognostic factors for acute acoustic trauma are difficult to predict. The aim of this study was to assess the prognostic factors of acute acoustic trauma. SUBJECTS AND METHOD: The cases selected for this report are 27 patients with acute acoustic trauma and 139 patients with sudden deafness are selected for control group. The following factors were examined for prognostic factors: age, vestibular symptom, degree of initial hearing loss, number of days before the start of treatment. RESULTS: Most strongly related factor for prognosis is number of days before the start of treatment, but other factors are not significant relation for prognosis. The overall hearing recovery rate of acute acoustic trauma was 29.6% and that of sudden deafness is 56.1%. CONCLUSION: Early treatment of acute acoustic trauma increases hearing recovery rate, and acute acoustic trauma has worse prognosis than sudden deafness.

A Transmission Electron Microscope Observation of Spiral Organ of Cochleae with Noise-induced Threshold Shift / 第二军医大学学报

Guinea pigs were exposed to either 110dB SPL white noise for 30min (ITS group )or 120 dB SPL for 150 nun (PTS group). At varying postexposure intervals, threshold shifts were assessed using auditory cortex evoked response to tone bursts and intracellular ultrastructural changes in the spiral organ of cochleae were exmained with a transmission electron microscope.. The threshold shifts induced by 110dB noise were reversible while those induced by 120dB noise were generally irreversible. In the TTS cochleae, damage was confined to the third row of OHCs where depolymerization of actin filaments within the stereocilia, slight celluar swelling and small vacuolization were found. The subnuclear area and nerve-endings were not involved. In the PTS cochleae, the inner hair cells (IHCs) and the first row of OHCs were affected. The abnormilities consisted of ruptures and holes in the cuticular plates, fusion of stereocilia, marked edema, tranclucence of subcuticular region, swelling of submembraneous cisterns and large vesiculation in the efferent nerve-endings blow OHCs. Based on the ultrastructural observations, structural bases in cochleae for TTS and PTS, sequence of pathological changes in hair cells as well as reversibility of specific pathologies were suggested.

NOISE-INDUCED MORPHOLOGIC CHANGES IN THE HAIR CELL NUCLEUS OF THE GUINEA PIG COCHLEA / 解放军医学杂志

To observe the morphological changes in hair cell nuclei in guinea pigs following noise exposure, guinea pigs were exposed to 4 kHz narrow band noise at 115 dB SPL for 4h. The cochleae were collected for the examination of the hair cell nuclei 14 days after the noise exposure. A fluorescent dye, Hoechst 33342,a fluorescent dye, was used to label the nuclear DNA and the specimens were examined under a fluorescence microscope for quantitative assessment of hair cell nuclear damage. There were three types of morphological changes in the damaged hair cell nuclei: nuclear swelling, nuclear condensation (karyopyknosis) and nuclear missing. Nuclear swelling was more frequent than nuclear missing. Nuclear condensation was less frequently found. The results suggested that complicated, long term and non synchronous biological processes might be involved in noise induced hair cell damage. A large number of hair cells with swollen nuclei, which might recover afte wards,still could be seen in the cochlea two weeks after noice exposure.

EXPERIMENTAL STUDY OF ACUTE ACOUSTIC TRAUMA IN INNER EAR / 第二军医大学学报

This is an experimental research into acute acoustic trauma free entirely from any explosive factor.The guinea pigs used in the different research groups of this experiment were exposed to narrow band noise of central frequency 1000 Hz and SPL 130 dB for one hour.Then the animals were killed and the cochlear basilar membranes were prepared into specimens at different periods for microscopic examination. Before the animals were exposed to noise, and were killed for preparation of specimens, the threshold values of the evoked potential of the cerebral cortex were respectively determined in the different groups so as to evaluate the hearing.The results show that the hearing loss was more serious and structural modification was slight at the earlier stage(i.e.on the day)and vice versa at the later stage (two weeks after).The mechanism of acoustic trauma may involve two aspects, i.e.local mechanical trauma and metabolic changes.At the earlier stage the main indication is mechanical trauma while at the later stage the structural modification is more evident, which may be induced by local metabolic changes.