放射性内耳损伤临床分析及黑色素在放射性内耳损伤中的保护作用研究

发布时间：2018-05-14 04:34

本文选题：感音神经性聋 + 鼻咽癌　；参考：《复旦大学》2012年博士论文

【摘要】：一鼻咽癌IMRT技术下放化疗患者放射性内耳损伤临床分析背景和目的我国是鼻咽癌高发国,放射治疗是目前最有效的治疗手段,同时,放射治疗也是其他头颈部恶性肿瘤的主要治疗方式之一[1]。近年来,头颈部肿瘤治疗后五年生存率有了明显提高,但随之而来的远期副反应也越来越被认识,其中放射性耳病发病率居晚期并发症的第二位[2]。放疗后感音神经性聋(Sensori-neural hearing loss,SNHL)是鼻咽癌放射治疗后的常见后遗症,尤其是联合化疗的患者更为常见,此种损害特点为延迟发生、进行性加重、不可逆的听力下降,而目前尚无有效的预防及治疗方法[3]。因此,在放疗患者中对内耳损伤的保护就显得尤为重要。随着放疗物理和放射生物的进展,调强放疗已成为鼻咽癌的标准放疗技术,放疗计划制定和实施中对内耳进行剂量限值成为可能。我们拟通过对骨导4K Hz电测听值作相关回顾性分析,了解鼻咽癌IMRT技术中化疗患者年龄、剂量等因素对SNHL发生率的影响,并尝试寻找耳蜗放疗剂量限定值,提供放疗计划制定中耳蜗剂量限值参考。材料与方法共有2009-2011年中29例(58耳)放化疗方案完全一致的病例进入此项研究。所有病例均为病理证实的初治鼻咽癌,行IMRT放射治疗和PF方案化疗。所有病例年龄≤55岁(以减少老年性SNHL对听力测试结果的影响),放疗前听力水平均正常(检测显示为正常电测听),在随访时均无肿瘤局部和区域复发及全身转移,有完整的体检记录及听力学检测资料包括耳鼓膜描述、电测听、声阻抗测试。入组时,我们排除放疗前后声阻抗鼓室图为B型的分泌性中耳炎患者(中耳积液有可能影响骨导测听值)。放疗前、放疗结束、放疗后3个月、放疗后6个月、放疗后1年、放疗后2年均随访电测听和声阻抗的情况,入组患者截止时点至少为放疗后12个月。以骨导4K Hz电测听值(阈值增大≥lOdB认为有意义)作相关线性回归分析、logistic分析和odds ratio分析,分析放射性内耳损伤相关因素,确定内耳剂量限定值。结果 58耳符合电测听分析条件,放疗后25.8%耳恶化。1.多元线性回归分析发现：放疗剂量(p=0.01,评估值0.46)、年龄(p=0.002,评估值0.47)均与SNHL发病率有统计学上的相关性。2.1ogistic回归分析发现：放疗剂量(p=0.02,评估值0.76)、年龄(p=0.005,评估值0.14)均与SNHL发病率有统计学上的相关性。3.OddsRatio分析发现：剂量评估值为1.001,年龄评估值为1.151,两者均是SNHL发病率的危险因素。4.对剂量与放疗后SNHL的发生率相关性的研究发现：良好组和恶化组之间剂量比较差异有统计学上的意义(良好组剂量36.87Gy,恶化组剂量39.43Gy,P=0.0492),我们推荐在放射治疗计划制定中耳蜗剂量应限值在37Gy以下。结论鼻咽癌IMRT技术下的放化疗患者,无论是线性回归模型、logstic回归模型还是Odds Ratio分析得出的结论一致。耳蜗照射剂量、年龄都与放疗后SNHL的发生率具有统计学上的相关性。为了预防IMRT技术下鼻咽癌放化疗患者SNHL的发生,推荐剂量值保持在37Gy以下。背景和目的我们的前期研究显示,鼻咽癌放化疗患者耳蜗放射剂量限制在37Gy可以预防SNHL的发生。以往研究报道,当耳蜗剂量达41-50Gy时,SNHL的发病率达31%,60-90Gy时更高达62%[4]。为保证鼻咽部肿瘤靶区的剂量,耳蜗剂量限定值以47Gy为宜[5],过低剂量限值可能影响肿瘤靶区剂量。因此,有必要寻找更多的内耳放射损伤保护方法。黑色素广泛分布于哺乳动物包括人的内耳中,如前庭暗细胞区、耳蜗血管纹、内淋巴囊等处的黑素细胞中[6]。大量文献证实,黑色素在噪音损伤、耳毒性药物和老年性耳聋中均有保护作用[7.8]。由于黑色素具有螯合金属阳离子的能力、氧化自由基清除能力,能量储存和转化能力[9],可能对耳蜗放射性损伤具有保护作用,但迄今为止尚未见相关报导。现有研究表明：杂色动物前庭、耳蜗和内淋巴囊内均有酪氨酸酶活性表达,因此杂色动物内耳黑素细胞能主动合成黑色素。白化动物则由于酪氨酸酶的遗传性缺陷,体内不能合成黑色素,因此白化动物内耳黑素细胞中没有黑色素分布[10]。由于白化和杂色豚鼠的内耳存在着上述差异,因此可以利用白化和杂色豚鼠相对比来研究黑色素在内耳中的功能。我们拟建造10Gy、15Gy、20Gy的豚鼠内耳损伤照射模型,然后通过比较两种豚鼠在三种剂量梯度下,在24小时和2周这两个时间截点上内耳损伤的差异,来探讨黑色素在放射性内耳损伤中是否具有保护作用。材料和方法将56只豚鼠分为杂色组和白化组,分别给予不照光、1000cGy、1500cGy、2000cGy照射,于照射后24小时和照射后2周断头处死,进行耳蜗铺片和制作冰冻切片,观察毛细胞、血管纹和螺旋韧带的损伤情况。1.选取第三回耳蜗基底膜进行耳蜗铺片,四氮唑蓝染色,镜下观察毛细胞排列情况,并进行细胞计数,计算缺失率。2.常规冰冻切片,HE染色,计量第三回血管纹的厚度,细胞密度,毛细血管数和螺旋韧带厚度及细胞密度。3.结果进行相关统计分析。研究结果在放射性内耳损伤模型中,研究结果如下：1.黑色素：白化组无论照射与否,均未见黑色素；杂色组随着照射剂量增加和照射后时间延长,黑色素有递增趋势,照射后2周黑色素增加更明显。2.毛细胞状况：随着照射时间延长和照射剂量的增加,两组豚鼠毛细胞紊乱和缺失率都有增加,但在同等剂量和时间条件下,白化组比杂色组排列更紊乱,缺失率更高。3.血管纹状况：随着照射剂量增加和照射后时间延长,白化组血管纹厚度减少,而杂色组基本不变,甚至有增厚趋势；照射后24小时,血管纹细胞数计数差别不明显。照射后2周,无论白化组还是杂色组,有核细胞都减少,白化组比杂色组减少更明显。4.毛细血管状况：照射后,两组豚鼠毛细血管数都增加,但两组之间差异不明显。5.螺旋韧带状况：随着照射剂量增加和照射后时间延长,两组豚鼠螺旋韧带纤维细胞均有减少的趋势,白化组比杂色组更明显。结论内耳黑色素量与内耳血管纹细胞、螺旋韧带细胞及基底膜毛细胞损伤变化呈负相关,此种相关性在照射后2周比照射后24小时更明显,但黑色素与血管纹微循环关系不明显。在放射性内耳损伤中,内耳黑色素与放射后SNHL的发生可能具有相关性,值得进一步研究。
[Abstract]:Clinical analysis of radiation induced inner ear injury in patients with nasopharyngeal carcinoma undergoing IMRT chemotherapy
Background and purpose
Radiotherapy is the most effective treatment for nasopharyngeal carcinoma in China. At the same time, radiation therapy is one of the main treatment methods for other head and neck malignant tumors, [1].. In recent years, the survival rate of five years after the treatment of head and neck tumor has been obviously improved, but the consequent long-term side effects are becoming more and more recognized. The second [2]. radiotherapy (Sensori-neural hearing loss, SNHL) after radiotherapy is a common sequelae after radiotherapy for nasopharyngeal carcinoma, especially in patients with combined chemotherapy, which is characterized by delayed onset, progressive weight, and irreversible hearing loss, but there is no effective preconditioning at present. As a result, the protection of the internal ear injury in patients with radiotherapy is particularly important. With the progress of Radiotherapy Physics and radiation biology, intensity modulated radiation therapy has become a standard radiotherapy technique for nasopharyngeal carcinoma. It is possible to limit the dose of the inner ear in the formulation and implementation of the radiotherapy plan. We intend to use the electrical audiometry value of 4K Hz for bone conduction. A retrospective analysis was made to understand the effect of age and dose on the incidence of SNHL in patients with nasopharyngeal carcinoma (IMRT), and to try to find the dose limited value of the cochlear radiotherapy, and to provide the radiotherapy plan for the reference of the dose limit of the cochlea.
Materials and methods
In a total of 2009-2011 years, 29 cases (58 ears) were fully matched to the study. All cases were confirmed by the pathology of nasopharyngeal carcinoma, IMRT radiotherapy and PF regimen chemotherapy. All cases were less than 55 years old (to reduce the effect of aging SNHL on hearing test results). The hearing levels before radiotherapy were normal (detection and display) For normal electrical audiometry, there were no local and regional recurrence and systemic metastases at the follow-up. Complete physical examination records and audiological data included the ear drum membrane description, electrical audiometry, and acoustic impedance test. When we entered the group, we excluded the acoustic impedance tympane of B type secretory otitis media before and after radiotherapy (the middle ear effusion may affect bone conduction. " 3 months after radiotherapy, 3 months after radiotherapy, 6 months after radiotherapy, 1 years after radiotherapy, 2 years after radiotherapy, and at least 12 months after radiotherapy at 2 years. Correlation linear regression analysis, logistic analysis and odds r were made with bone guided 4K Hz audiometric value (threshold value greater than lOdB) Atio analysis, analysis of factors related to radiation inner ear injury, determine the dose limit of inner ear.
Result
The 58 ears were in accordance with the conditions of electrical audiometry, and the 25.8% ear worsening.1. multivariate linear regression analysis after radiotherapy found that the dose of radiotherapy (p=0.01, evaluation value 0.46), age (p=0.002, evaluation value 0.47) were all statistically correlated with the incidence of SNHL,.2.1ogistic regression analysis was found: dosage (p=0.02, evaluation value 0.76), age (p=0.005, evaluation value 0.14). A statistically significant correlation with the incidence of SNHL was found in.3.OddsRatio analysis: the dose assessment was 1.001 and the age assessment was 1.151. Both were the risk factors for the incidence of SNHL. The correlation between the dose and the incidence of SNHL after radiotherapy was found to be statistically significant in the dose comparison between the good group and the worsening group. The best dose is 36.87Gy, the dose of deterioration group is 39.43Gy, P=0.0492). We recommend that the cochlear dose limit should be below 37Gy in the formulation of radiotherapy plan.
conclusion
Patients with nasopharyngeal carcinoma (nasopharyngeal carcinoma) with IMRT technique are consistent with the results of linear regression model, logstic regression model or Odds Ratio analysis. The dose of cochlear irradiation and age are statistically related to the incidence of SNHL after radiotherapy. In order to prevent the occurrence of SNHL in patients with nasopharyngeal cancer chemoradiotherapy under IMRT Technology, the recommended dose values are recommended. Keep it below 37Gy.
Background and purpose
Our previous study showed that the dose limit of the cochlear radiation dose to 37Gy in patients with nasopharyngeal carcinoma could prevent the occurrence of SNHL. In the previous study, when the cochlear dose reached 41-50Gy, the incidence of SNHL was 31%, and 62%[4]. was more than 62%[4]. to ensure the dose of the target area of the nasopharyngeal tumor. The cochlear dose limited value was [5] with 47Gy as appropriate, and the low dose limit was limited. The value may affect the dose of tumor target area. Therefore, it is necessary to find more protection methods for radiation injury of inner ear.
Melanin is widely distributed in mammals including human inner ears, such as the vestibule dark cell areas, the cochlear veins, and the endolymphatic sac, which are widely documented in [6].. Melanin is protected by noise damage, ototoxic drugs and senile deafness, the ability of [7.8]. to be oxidized by melanin with chelating metal cations. Free radical scavenging ability, energy storage and transformation capacity [9] may have protective effects on the cochlear radiation damage, but so far no related reports have been reported. The present study shows that tyrosinase activity is expressed in the vestibule, cochlea and endolymphatic sac of the colored animals. Therefore, melanin cells in the clutter animal can be active in synthesizing melanin. Because of the genetic defects of tyrosinase and the inability of the body to synthesize melanin, the non melanin distribution in the melanocytes of albino melanocytes in the albino animal's inner ear [10]. has the above differences due to the albino and the inner ear of the variegated guinea pigs. Therefore, the function of melanin in the inner ear can be studied by the contrast of albino and variegated guinea pigs. In order to explore the protective effect of melanin on the inner ear injury of radioactive inner ear by comparing the damage of the inner ear of the two guinea pigs at the 24 and 2 weeks at the 24 and 2 weeks, the internal ear injury model of 10Gy, 15Gy and 20Gy was built.
Materials and methods
56 guinea pigs were divided into the color group and the albino group. They were irradiated with no light, 1000cGy, 1500cGy, 2000cGy, 24 hours after irradiation and 2 weeks after irradiation. The cochlear slices and frozen sections were made to observe the damage of the hair cells, vascular lines and spiral ligaments. The third cochlear basement membrane was selected for the cochlear tablet and tetrazolium. Blue staining, observed the arrangement of hair cells under the microscope, and counted the cells, calculated the loss rate.2. conventional frozen section, HE staining, measured the thickness of third blood vessels, cell density, the number of capillary and the thickness of spiral ligament and cell density.3. results.
Research results
In the radiation injury model of inner ear, the results are as follows: 1. melanin: no matter the irradiation or not, no melanin is found in the albino group. With the increase of irradiation dose and the prolongation of the time after irradiation, the melanin has a tendency to increase. The increase of melanin in the 2 weeks after irradiation is more obvious.2. capillary cell condition: with the prolongation of the irradiation time and the dose of irradiation. In addition, the hair cell disorder and loss rate of the two groups of guinea pigs increased, but in the same dose and time condition, the albino group was more disorder than the color group, and the loss rate was higher than that of the.3.. With the increase of irradiation dose and the prolongation of the irradiation time, the vascular thickness of the albino group decreased, and the color group was basically unchanged, even thickening trend. At 24 hours after irradiation, the number of vascular cell counts was not significant. At 2 weeks after irradiation, the nucleated cells decreased and the whitening group decreased more obvious.4. capillary conditions than the color group. After irradiation, the number of capillaries in the two groups of guinea pigs increased, but the difference between the two groups was not evident in the.5. spiral ligament condition: with the illumination. After the increase of radiation dose and prolonged irradiation time, the two groups of guinea pig spiral ligament fibroblasts showed a decreasing trend, and the albino group was more obvious than the color group.
conclusion
The amount of melanin in the inner ear was negatively correlated with the damage and changes of the inner ear vascular cells, the spiral ligament cells and the basal membrane hair cells. This correlation was more obvious at 2 weeks after irradiation than the 24 hours after irradiation, but the relationship between melanin and vascular microcirculation was not obvious.
In the radiation inner ear injury, melanin in the inner ear may be related to the occurrence of SNHL after radiation. It is worth further studying.

【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R764

【参考文献】