Evaluation of serum prolidase enzyme activity and oxidative stress in patients with tinnitus

Abstract Introduction Tinnitus is defined as the perception of sound in the head or in the head in the absence of external sounds. The cause of tinnitus is still unknown. Objective We aimed to compare the serum levels of total oxidant status, total antioxidant status, serum prolidase enzyme activity and the oxidative stress index in patients with tinnitus to those of normal subjects. Methods Twenty five patients with tinnitus (mean age 34.3) and 25 healthy controls (mean age 37.2) were included in the study. Results Total oxidant status levels in the patient group were significantly higher than in the control group (p = 0.037). The mean total oxidant status value was 2.54 ± 0.95 mmoL/L in the patient group, and 2.06 ± 0.98 mmoL/L in the control group. The mean oxidative stress index level was 0.22 ± 0.10 AU in the patient group, while it was 0.17 ± 0.08 AU in the control group. Oxidative stress index was significantly higher in the patient group (0.026). There was no significant difference between the groups in terms of total antioxidant status values (p = 0.838). The mean serum prolidase enzyme activity level was 202.74 ± 33.56 U/L in the patient group and 175.46 ± 42.68 U/L in the control group. Serum prolidase enzyme activity levels in the patient group were significantly higher than in the control group (0.040). Conclusion We detected that the total oxidant status, oxidative stress index and serum prolidase enzyme activity levels were higher in patients with tinnitus when compared to the healthy controls. This finding suggests that oxidative stress index and serum prolidase enzyme activity may play a role in the etiopathogenesis of tinnitus.

摘要
引言 耳鸣被定义为在无外界声源存在的情况下，头部内产生的声音感知。目前耳鸣的病因仍未明确。
研究目的 本研究旨在对比耳鸣患者与健康受试者的血清总氧化状态、总抗氧化状态、血清脯氨酸肽酶（prolidase enzyme）活性以及氧化应激指数水平。
研究方法 本研究共纳入25名耳鸣患者（平均年龄34.3岁）与25名健康对照者（平均年龄37.2岁）。
研究结果 患者组的总氧化状态水平显著高于对照组（p=0.037）。患者组的平均总氧化状态值为2.54±0.95 mmol/L，对照组为2.06±0.98 mmol/L。患者组的平均氧化应激指数为0.22±0.10 AU，对照组为0.17±0.08 AU，患者组氧化应激指数显著更高（p=0.026）。两组的总抗氧化状态水平无显著差异（p=0.838）。患者组的平均血清脯氨酸肽酶活性为202.74±33.56 U/L，对照组为175.46±42.68 U/L，患者组的血清脯氨酸肽酶活性显著高于对照组（p=0.040）。
研究结论 本研究发现，与健康对照者相比，耳鸣患者的总氧化状态、氧化应激指数及血清脯氨酸肽酶活性水平均更高。该结果提示，氧化应激指数与血清脯氨酸肽酶活性可能在耳鸣的病因发病机制中发挥作用。