[Clinical observation on the effect of glucocorticoid insensitivity on sudden sensorineural hearing loss patients]

Objective: To investigate the correlation between the proliferation inhibition effect of glucocorticoid (GC) on peripheral blood mononuclear cell (PBMC) and the pure tone average (PTA) improvement in SSNHL patients. Methods: Sixty inpatients with SSNHL were included from July 2013 to October 2015 in Nanjing Drum Tower Hospital, Medical School of Nanjing University. Peripheral venous blood was collected before receiving treatment, then the PBMC was isolated for GC proliferation inhibition. PBMCs of each patient were cultivated into 4 groups: Group A: PBMCs+ Medium; Group B: PBMCs+ Medium+ lipopolysaccharide (LPS, 1 μmol/L); Group C: PBMCs+ Medium+ LPS+ Dexamethasone; Group D: Medium. PBMCs were maintained in a humidified 5% CO(2) atmosphere at 37°C and were observed after 24 hours. 5-diphenyltetrazolium bromide (MTT) was used to measure PBMC proliferation inhibition rate. The PBMC proliferation inhibition rates were calculated according to the absorbance at 490 nm wavelength under a microtiter plate reader. Independent sample t tests of PBMC proliferation inhibition rate were performed between different groups. χ(2) tests were performed between gender, affected ear side, accompanied by vertigo or not, audiometric curve, time period from onset to treatment, PBMC proliferation inhibition rate and the improvement of pure tone average (PTA). Linear correlation analyses were performed between PBMC proliferation inhibition rate, the time period from onset to treatment and the hearing improvement. Results: The proliferation inhibition effect of GC on PBMC varied significantly among patients. The PBMC proliferation inhibition rate in GC insensitive group was lower than that in GC sensitive group (26.72%±21.82% vs 64.44%±25.48%, t=6.113, P<0.05). The PBMC proliferation inhibition rate in refractory group was lower than that in initial group (40.93%±28.57% vs 57.04%±31.19%, t=2.035, P=0.046). There was no statistical significance between gender, affected ear side, accompanied by vertigo or not, audiometric curve and the hearing improvement (χ(2) value was 2.320, 0.031, 2.143, 0.106, respectively, all P>0.05). Both in initial group and refractory group, the linear correlation analyses showed a significant positive correlation between PBMC proliferation inhibition rate and the PTA improvement (r value was 0.615, 0.657, respectively, all P<0.05), as well as a significant negative correlation between time period from onset to treatment and the PTA improvement(r value was -0.542, 0.370, respectively, all P<0.05). Conclusions: The proliferation inhibition rate of PBMC in vitro by GC is correlated with patients' hearing improvement. The proliferation inhibition test might be used to predict the sensitivity to GC treatment and be helpful for individualized treatment of SSNHLin clinical practice.