目的 探讨脑源性神经营养因子(BDNF)及Val66Met基因多态性与耳鸣的关系，评价耳鸣疗效及耳鸣程度与血浆BDNF的相关性。方法 测定30例耳鸣患者(实验组)和30例健康对照者(对照组)血清BDNF水平及其基因多态性(rs 6265Val66Met)。耳鸣严重程度使用耳鸣残疾评估量表(THI)评估。根据THI评分将耳鸣患者分为两组：轻度残疾(≤36分)和中重度残疾(≥38分)。所有患者使用经颅磁刺激治疗。以耳鸣残疾评估量表(THI)评分、血浆BDNF浓度治疗前后变化情况，探讨耳鸣程度及疗效与血浆BDNF浓度的关系。结果 耳鸣患者血清BDNF浓度低于健康对照组(P＜0.05)。耳鸣治疗有效患者治疗后血清BDNF浓度高于治疗前血清BDNF(P＜0.05)；耳鸣治疗无效患者治疗前后血清BDNF浓度变化无统计学意义。在耳鸣患者和健康对照组中，BDNF(rs 6265Val66Met)基因多态性与血清BDNF浓度均无明显相关性。结论 BDNF的浓度与耳鸣的预后存在相关性，BDNF可能通过神经可塑性机制参与耳鸣疾病的发生；因此推测血清BDNF浓度可以作为耳鸣疗效的客观指标之一。
Objective To discuss relationships of brain-derived neurotrophic factor (BDNF) and its Val66Met gene polymorphism with chronic tinnitus, and determine the correlations between the therapeutic effect and severity of tinnitus and serum BNDF concentration.Methods Serum levels of BDNF and its rs 6265Val66Met gene polymorphism were measured in 30 patients with tinnitus (study group) and 30 healthy controls (control group). The severity of tinnitus was assessed using the tinnitus handicap inventory (THI). All the tinnitus patients were divided into two groups according to the THI score: mild group (THI≤36 score) and moderate to severe group (THI≥38 score). All patients were treated with transcranial magnetic stimulation. The changes of THI score and serum BDNF level before and after treatment in the study group were observed to determine the correlations between the therapeutic effect and severity of tinnitus and serum BNDF concentration.Results The serum BDNF concentration in the study group was lower than that in the control group (P<0.05). The serum BDNF concentration after treatment was higher than that before treatment in the tinnitus patients who had responded to treatment (P<0.05), while the serum BDNF concentration did not change significantly in the tinnitus patients who had not responded to treatment. In both the study group and the control group, there was no significant correlation between the gene polymorphism of BDNF (rs 6265Val66Met) and the serum BDNF concentration.Conclusion The serum concentration of BDNF is correlated with the prognosis of tinnitus, and BDNF may be involved in the occurrence of tinnitus through the mechanism of neuroplasticity. Therefore, it is speculated that serum BDNF concentration may be used as one of the objective indicators of therapeutic effect in tinnitus.