Screening And Identification Of Differential Proteins Of Serum In Individuals Susceptible To Noise Induced Hearing Loss In Tunnel

Noise-included hearing Loss(NIHL)is one kind of sensorineural hearing loss caused by long-term exposure to noise.Oxidative stress(OS)is considered to be the main cause of cochlear damage by noise.Troops responsible for military sap construction of PLA distribute in tunnel in an enclosed environment year by year.The noise level in such environment always exceeds the safety level,which might easily cause NIHL.It is reported that the susceptibility of NIHL exits and varies among different individuals.Therefore it is meaningful to study the screening measures of susceptible individual to NIHL in troops working in military tunnel for saving battle effectiveness and realizing the objective of building a strong army.Up to now,most researches on NIHL susceptibility focused on a sole gene and there is no effective screening method of susceptible individuals.Protein is the main element for organism performing physiological function.The development of technique of proteomics has provided a new technology platform for overall study on NIHL susceptibility mechanism and a technical basis of looking for specific biomarkers for NIHL susceptible individuals.Through research on serum differential protein of soldiers from a certain tunnel construction troop by differential proteomics method,this paper preliminarily studied the expression of differential protein in NIHL susceptible individual.The result provided reliable experimental basis for the study of specific biomarkers in NIHL susceptible individuals serum.MethodsAccording to our previous epidemiological survey result,soldiers from one tunnel construction troop were divided into susceptible group and nonsusceptible one.Twenty soldiers were selected from both groups each.They were all male with age from 18 to 39.The average age was 24.79±2.03 and 23.67±3.56 years old.There was no significant difference of age between susceptible group and nonsusceptible one(p>0.05).Their peripheral venous blood samples were collected.After removing high abundant proteins and determining protein concentration of these samples,2-DE was used to separate proteins in the serum.Then the peptide fingerprinting was obtained by MALDI-TOF/MS,and matched them with database from NCBI using Mascot software.The results were analyzed by one-way ANOVA and t test using STATA9.0 software,and P<0.05 means statistical significance.Results1120 protein spots were found after 2-DE,including 37 protein spots differentially expressing between NIHL susceptible group and nonsusceptible group.The overall gray value of susceptible group was lower compared to nonsusceptible group and the difference was statistically significant(t=-2.758,P=0.0091).Among the 37 differential proteins,there were 22 spots unregulated in susceptible group and 16 peptides were identified by mass spectrometry.There were 15 differential proteins down regulated in susceptible group and MS identified 12 peptides.After compared by mascort score,10 differential proteins were harvested.They were complement C4-A,lysozyme C,beta-2 glycoprotein-1,transthyretin,pigment epithelium derived factor,35 kDa trypsin inhibitor heavy chain H and proteasome subunit alpha-5,haptoglobin,vitronectin and apolipoprotein A-I.Among these 10 differentially expressed proteins,5 peptides including proteasome subunit alpha-5,complement C4-A,haptoglobin,apolipoprotein A-I and Vitronectin were upregulated,and 5 ones including Lysozyme C,beta-2 glycoprotein-1,pigment epithelium derived factor,35 kDa trypsin inhibitor heavy chain H and transthyretin were downregulated in NIHL susceptible individuals.The differences were statistically significance(P<0.05).Conclusion:Our research identified differentially expressed plasma proteomes of NIHL susceptible individuals by 2-DE and MALDI-TOF/MS platform,and 10 peptides with significant differential expression were found.From this study,2 conclusions could be drawn as follows:1.The differentially expressed 2-DE maps were established successfully in NIHL susceptible individuals and nonsusceptible ones.37 differentially expressed protein spots were picked.There were 28 proteins identified by mass spectrometer successfully.Except for peptides with mascort score lower than 66,10 proteins were harvested.2.Among these 10 differentially expressed proteins,eight ones including proteasome subunit alpha-5,complement C4 A,haptoglobin,apolipoprotein A-I,beta-2 glycoprotein-1,pigment epithelium derived factor,35 kDa trypsin inhibitor heavy chain H and transthyretin,closely related to oxidative stress response.It is suggested that in NIHL susceptible individuals,dysfunction of many regulation system related to oxidative stress response might be one of the primary reason of NIHL susceptibility.Proteins harvested from this study were expected to be specific candidate serum NIHL susceptibility biomarkers in blood to help screen susceptible individuals.Further study was needed to verify these proteins in other NIHL susceptible individuals.According to the results above,the candidate differential proteins might paly an important role in the NIHL susceptibility,and these peptides may become the specific serum biomarkers for NIHL susceptible individuals in the future.Proteomics technology provides a new pathway for screening biomarkers related to NIHL susceptibility in blood to help find susceptible individuals.