皮肤鳞状细胞癌小鼠模型的光声成像及光声谱分析

Photoacoustic imaging and photoacoustic spectrum analysis in mouse models of cutaneous squamous cell carcinoma

目的初步建立皮肤肿瘤光声检测系统与数据处理方法,并对皮肤鳞状细胞癌(鳞癌)模型进行光声成像和光声谱分析。方法6~8周龄健康雌性SPF级BALB/C裸鼠60只,分别用小鼠皮肤鳞癌XL50细胞(30只)和人皮肤鳞癌A431细胞(30只)接种裸鼠背部右侧近上肢处,成功构建小鼠皮肤鳞癌和人皮肤鳞癌动物模型各20只。在850nm波长下应用光声检测系统采集上述两种模型在体光声成像和光声谱数据,对鳞癌和背部左侧正常皮肤声功率谱曲线拟合斜率进行比较。光声检测完成后,取两种模型小鼠肿瘤组织及对侧正常皮肤行组织病理检查。不同组织拟合斜率的比较采用t检验。结果光声成像显示,鳞癌瘤体与正常组织相比具有更丰富的血红蛋白光声信号。同时,XL50小鼠皮肤鳞癌裸鼠模型肿瘤组织声功率谱拟合斜率(-1.827±0.1531)低于正常皮肤组织(-1.059±0.1178),t=3.973,P<0.001;A431人皮肤鳞癌为-1.537±0.1255,亦低于正常皮肤组织(-0.960±0.2597),t=2.166,P=0.043。组织病理显示,肿瘤组织较正常组织血管增多。结论皮肤鳞癌与正常皮肤组织的光声成像信号与光声谱的声功率谱拟合斜率存在差异,为皮肤鳞癌的无创光声诊断奠定基础。

Objective To establish a photoacoustic detection system and data processing methods for skin tumors,and to explore photoacoustic imaging and photoacoustic spectrum in mouse models of cutaneous squamous cell carcinoma(CSCC).Methods A total of 60 healthy specific pathogen-free(SPF)female BALB/C nude mice aged 6-8 weeks were randomly and equally divided into 2 groups to be inoculated with a murine CSCC cell line XL50 and a human CSCC cell line A431 respectively on the right back near the upper limbs,and mouse models of murine CSCC(n=20)and human CSCC(n=20)were successfully established.The 850-nm photoacoustic detection system was applied in the above 2 kinds of mouse models,and photoacoustic imaging and photoacoustic spectrum data were collected.The fitted slope of acoustic power spectrum curves was compared between squamous cell carcinoma tissues and normal skin on the left back of the mouse model.After the photoacoustic detection,tumor tissues and normal skin at the opposite side were excised from the 2 kinds of mouse models,and subjected to histopathological examination.The fitted slope of different tissues was compared by using t test.Results Photoacoustic imaging showed higher photoacoustic signals of hemoglobin in squamous cell carcinoma tissues compared with the normal skin tissues.In the model of murine CSCC,the fitted slope of acoustic power spectrum curve was significantly lower in the tumor tissues(-1.827±0.153 1)than in the normal skin tissues(-1.059±0.117 8,t=3.973,P<0.001).In the model of human CSCC,the fitted slope of acoustic power spectrum curve was also significantly lower in the tumor tissues(-1.537±0.125 5)than in the normal skin tissues(-0.960±0.259 7,t=2.166,P=0.043).Histopathological examination showed that the number of vessels increased in the tumor tissues compared with the normal skin tissues.Conclusion CSCC tissues are different from normal skin tissues in photoacoustic imaging signals and the fitted slope of acoustic power spectrum,which may lay a foundation for non-invasive photoacoustic diagnosis of CSCC.