Saturated Hydrogen Saline On Noise-induced Hearing Loss Prevention Research

Currently, more and more people are suffering Noise Induced Hearing Loss（NIHL）. Hearing impairment caused by noise are mostly irreversible neurologicaldamage. At present, there are no effective treatment methods, which is the focus ofhearing prevention research. The latest study found that drinking saturation hydrogenwater could reduce the hearing impairment caused by white noise[1]. But themechanism of action remains unclear, needed to reveal the characteristics of its ownof further studies. This is experiment designed by intraperitoneal injection of saturatedhydrogen saline, the first time from the auditory function, morphology andbiochemistry to explore the saturated hydrogen saline prevention of impulsenoise-induced hearing damage and treatment of the role of its protection mechanism.PART ONE Saturated hydrogen saline animal protection model of noiseinduced hearing lossObjective To explore the saturated hydrogen saline on the preventive effect ofnoise induced hearing loss noise by establishing hearing loss animal models. MethodsTake clean male white health, normal ABR threshold in guinea pigs18, body weight250～300g. The guinea pigs were randomly divided into5groups:2guinea pigs innormal group,4guinea pigs in blank control group （pure noise exposure）,4guineapigs in saline control group （1hour before noise exposure given intraperitonealinjection of an equal volume of saline,1ml/100g）,4guinea pigs in saturatedhydrogen saline group,4guinea pigs in saturated hydrogen saline-treated group, in1hour before noise exposure given intraperitoneal injections of saturated hydrogensaline,1ml/100g. One hundred rounds of impulse noise （157dB SPL peak） weredelivered as noise exposure. Four hours and14days after impulse noise exposure, simples by scanning electron microscopy observed. Results Scanning electronmicroscopy results showed that noise exposure after4hours, blank control group andthe saline control group, pervasive lack of hair cell cilia and integration of all themissing three rows of stereocilia of outer hair cells, outer hair cells heaviestlydamaged in the semi-circle on the bottom circle beween second circle. Saturatedhydrogen saline-treated group cilia lossing were significantly less than the controlgroup.14days of the cochlear hair cell damage after noise exposure were more worsethan the noise exposure after4hours. Conclusion We successfully constructed noisedeafness animal models, saturated hydrogen saline had some preventive effect ofnoise induced hearing loss, could significantly reduce the strong impulse noise oninner ear damage.PART TWO Saturated hydrogen saline protects and repairsnoise-induced hearing lossObjective To explore the best delivery time and saturated hydrogen salinerepairment of the noise induced hearing loss. Method Immediately after exposure toimpulse noise and on Days1,2,4and8following exposure, auditory brainstemresponse（ABR） were measured. By eighth days of succinate dehydrogenase （SDH）、silver nitrate （AgNO₃） histochemistry staining and immunohistochemical stainingobserve the morphological changes of the hair cells. Results After noise exposure, thesaturated hydrogen saline treated group1h ABR thresholds were significantly lowerthan the control group（p<0.05）. Saturated hydrogen saline for1hour,2hours groupABR threshold degree of recovery were significantly faster than the blank controlgroup and the saline control group （P <0.05）. Morphological results showed thatsaturated hydrogen saline-treated1hour group of outer hair cells and cilia loss weresignificantly reduced performance. Conclusion One hour before noise exposure givenintraperitoneal injection of saturated hydrogen saline can effectively antagonize thestrong impulse noise-induced cochlear injury and play a certain degree of NIHLprevention and repairment. PART THREE Saturated hydrogen saline prevention mechanism of noiseinduced hearing lossObjective Through the detection of guinea pig plasmatotal of superoxidedismutase （T-SOD） activity, superoxide anion （O₂-） activity, malondialdehyde （MDA）content and T-SOD anda O₂-activity of cochlear tissues to study the mechanism ofsaturated hydrogen saline on the prevention and treatment of NIHL. Methods Twohours before noise exposure and two hours after noise exposure, tooked bloodsamples to detect the plasma T-SOD and O₂-activity, MDA content; after taking bloodimmediately decapitated guinea pigs and removed bilateral cochlear to determinationthe T-SOD an O₂-activity of the cochlear tissues. Results T-SOD、O₂-activity andMDA content in the plasma were not statistically different before and after noiseexposure; T-SOD activity between the cochlear tissues in the blank group and thesaline control group had no significant difference （P>0.05）, but between normalgroup and saturated hydrogen saline-treated1hour group had a statisticallysignificant difference （P<0.05）. Conclusion Saturated hydrogen saline hadantioxidant properties, could effectively remove large amounts of oxygen free radicalsin the cochlear tissue to reduce the damage of the NIHL.PART FOUR Strong noise caused changes of arterial blood gas andelectrolyte of the adult guinea pigObjective To investigate the impact of arterial blood gas and electrolyte of adultguinea pigs by impluse noise exposure. Method Each group were exposed by impulsenoise, immediately after,1h,2h,4h pericardial puncture blood is approximately1mlmeasured arterial blood gas and K⁺, Na⁺, Cl^-, Ca²⁺concentration. Results after noiseexposure, arterial blood gas pH values were maintained within the normal range offluctuation, at different time points were not statistically different （P>0.05）; calciumconcentration immediately、1h after noise exposure, the blank control group increasedwith the normal group, was significantly difference from the saturated hydrogensaline group （P <0.05）; potassium ion concentration immediately after noise exposure,the blank control group and the hydrogen saturated saline-treated group were significantly different,（P <0.05）; the concentration of sodium ions after noiseexposure, normal group and the rest of the group were statistically significant （P<0.05）. Conclusion Arterial blood gas pH and plasma Ca²⁺concentration in guineapigs may be increased after implus noise explosure.