Effect of hydroxysafflor yellow a on γ-aminobutyric acid and glutamic acid levels in the inferior colliculus of rats with tinnitus / 国际中医中药杂志

ABSTRACT

Objective:To evaluate the therapeutic effect of hydroxysafflor yellow A (HYA) on rats with tinnitus and investigate its influence on γ-aminobutyric acid (GABA) and glutamic acid (Glu) levels of inferior colliculus.Methods:The model of rats with tinnitus received an injection of sodium salicylate and "water-drinking suppression" was extablished, and then were divided into four groups with random number table method: normal group, model group, positive control (carbamazepine 5 mg/kg) and HYA (20 mg/kg) groups. Animals were intraperitoneally injected for 15 days. The recovery time of water-drinking suppression of all groups were recorded. The threshold value of auditory brainstem response (ABR) under the different frequency (4, 12, 20 and 28 kHz) in each rat was measured. The levels of GABA and Glu in inferior colliculus in rats with tinnitus were detected by LC-MS/MS.Results:Compared with the model group, the recovery time of water drinking suppression [(3.55±0.69)d vs.(1.83±0.58)d] in HYA group was significantly prolonged ( P<0.01). Compared with the model group, the threshold value of ABR under different frequency (4, 12, 20 and 28 kHz) were significantly reduced in HYA group ( P<0.01). The GABA levels [(2.25±0.26) μmol/g vs.(1.96±0.19)μmol/g] in inferior colliculus of tinnitus rats in HYA group was significantly increased ( P<0.05) while the Glu levels [(2.95±0.34)μmol/g vs.(3.71±0.39)μmol/g] were significantly decreased ( P<0.01). Conclusion:HYA treatment could relieve tinnitus symptoms induced by sodium salicylate, which might be related to the recovery of excitatory/inhibitory neurotransmitter balance.