聚焦超声用于猪皮下脂肪减脂有效性的实验研究

发布时间：2018-09-13 07:26

【摘要】：研究背景从上个世纪末，超声治疗技术开始在国际领域内兴起，超声治疗包括了高强度聚焦超声（HighIntensityFocusedUltrasound,HIFU）治疗和聚焦超声治疗（FocusedUltrasound,FU）。HIFU的声强一般为几千到几万瓦/cm2，由于其具有良好的组织穿透性和聚焦性等特点，已广泛应用于如乳腺癌、子宫肌瘤、肝癌、骨肉瘤、前列腺癌等[1-6]实质性脏器占位性肿瘤的治疗。FU的声强一般几十到几百瓦/cm2，主要利用超声的机械效应，空化效应，热效应以及功能调节作用，通过改善靶区组织的生长环境来促进微血管的形成，从而使得组织得以修复或再生，目前已经用于治疗慢性宫颈炎，外阴上皮内非瘤样病变，外阴尖锐湿疣，变应性鼻炎等方面的治疗并取得良好疗效。超声治疗除了在各种实质性肿瘤和炎症的治疗方面有广泛应用外，目前在减脂塑形领域也是一大研究热点。本课题从离体和活体两个方面探究聚焦超声在不同辐照剂量下对猪皮下脂肪的破坏效应，旨从靶区脂肪的破坏效应和声通道上组织破坏情况两个方面，，探讨聚焦超声破坏猪皮下脂肪的有效性及筛选出的理想辐照剂量，为后期进一步研究奠定基础。目的利用聚焦超声作用于离体和活体猪皮下脂肪，通过对靶区脂肪破坏效应的观察，为应用体外聚焦超声实现临床减脂塑型提供实验基础，并为减脂塑型领域补充治疗技术。方法 1.离体实验部分选用屠宰后6h内的新鲜离体猪皮下脂肪块210块（带皮，每块大小为3cm×3cm×3cm）。分成A、B两组，A组120块（A1=60，A2=60），B组90块（B1=60，B2=30）。A1组用于肉眼观察，A2组用于MTT检测，B1组用于光镜观察，B2组用于靶区及辐照区温度检测。使用FU的辐照功率为200W，辐照时间：A组为5、10、20、30、60、90s，B组为30、60、90s，合成不同剂量的聚焦超声作用于脂肪块。通过对靶区及辐照区皮肤的靶区肉眼、MTT染色，光镜观察，温度检测，探讨聚焦超声破坏离体猪脂肪的有效性及提供后期活体实验的剂量参考。 2.活体实验部分家猪2头（体重约为130～140kg），编号为甲、乙。选用功率（100、150、200）W和时间（15、30、60）s组合成9种不同的剂量，每种剂量在每次实验中作用三个不同的辐照点，各一次。选择猪两侧腹壁脂肪层较厚的地方为辐照区，甲猪选择一块实验区（36个辐照点），于实验后第1天处死；乙猪选择左右两侧两块实验区（左侧36个辐照点，右侧36个辐照点），左侧第1天实验，右侧第23天实验，在第一次实验后的30天处死。通过实验前后血脂检测，实验后取靶区、辐照区皮肤、重要脏器（心和肝）行组织学检测，B超测量乙猪在辐照前及辐照后第2、7、23、30天各辐照区脂肪层厚度的变化，探讨聚焦超声破坏活体猪皮下脂肪的有效性及疗效观察。结果 1．离体实验部分： (1)当使用辐照时间为5s的聚焦超声作用于脂肪块后：肉眼及MTT(3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide，MTT)染色检测未见凝固性坏死； (2)在10、20、30、60、90s的时间剂量中，靶区坏死体积、组织学变化，辐照区皮肤和靶区温升与辐照时间成正比。当辐照时间为90s时，出现皮肤发白变硬的现象。 2.活体实验部分： (1)大体观察：200W的功率和30s、60s的辐照时间作用后的靶区均见的灰白色凝固性坏死灶； (2)光镜（LightMicroscope,LM）观察：靶区脂肪做HE染色（Hematoxylin-Eosin，HE）结果显示FU在不同辐照剂量下对活体猪皮下脂肪组织呈现不同的破坏作用：当能量过低时，FU对皮下脂肪的破坏作用不明显，当给予的能量达到一定阈值（200W）后，随辐照时间的增加（≤60s），靶区的破坏程度越大，而靶区周围的血管神经结构完整。在辐照后30天取靶区组织，苦味酸天狼星红染色（SiriusRed-PolarizationStaining,SRP）发现200W，30s和60s均出现纤维化。重要脏器（心和肝）形态结构正常，未出现脂肪化； (3)电镜（ElectronMicroscope，EM）观察：辐照功率200W，辐照时间60s作用后的靶区出现纤维化和泡沫细胞； (4)B超测量除100W，15s外辐照区皮下脂肪厚度均较空白对照组出现不同程度的减少（P＜0.05），在功率为200W，辐照60s时的厚度减少最明显。血脂检测实验前后各血脂指标无差异（P0.05）。结论聚焦超声能有效破坏猪皮下脂肪，而对靶区周围的血管神经无损伤。实验结果表明，辐照功率为200W，辐照时间为30～60s时靶区的破坏程度明显，可能为破坏猪皮下脂肪的最佳参数。
[Abstract]:Research background
From the end of last century, ultrasound therapy technology began to rise in the international field. Ultrasound therapy includes high intensity focused ultrasound (HIFU) treatment and focused ultrasound therapy (FU). HIFU usually has the intensity of tens of thousands to tens of thousands of watts / cm 2, because of its good tissue penetration and focusing characteristics. FU has been widely used in the treatment of solid organ occupying tumors, such as breast cancer, uterine fibroids, liver cancer, osteosarcoma, prostate cancer, etc. [1-6]. The intensity of FU is usually tens to hundreds of watt/cm 2, mainly using the mechanical effect of ultrasound, cavitation effect, thermal effect and function regulation to promote micro-effects by improving the growth environment of target tissue. Vascular formation, which allows tissue to be repaired or regenerated, has been used to treat chronic cervicitis, vulvar intraepithelial non-neoplastic lesions, vulvar condyloma acuminatum, allergic rhinitis and other aspects of treatment and achieved good results.
Ultrasound has been widely used in the treatment of various solid tumors and inflammation, but it is also a hot research topic in the field of lipid-reducing and shaping. In this paper, the destructive effects of focused ultrasound on subcutaneous fat of pigs under different irradiation doses were investigated in vitro and in vivo, aiming at the destructive effects of target fat and acoustic channels. The effectiveness of focused ultrasound in destroying porcine subcutaneous fat and the optimal irradiation dose screened were discussed from the two aspects of upper tissue destruction, which laid a foundation for further study.
objective
Focused ultrasound was used to treat subcutaneous fat of pig in vitro and in vivo. Through the observation of the destructive effect of fat in the target area, the experimental basis was provided for the application of focused ultrasound in vitro to achieve clinical lipid reduction and plasticity, and the supplementary treatment technology in the field of lipid reduction and plasticity was provided.
Method
1. in vitro experiment
210 pieces of fresh porcine subcutaneous fat were divided into two groups: group A (120 pieces A1 = 60, A2 = 60), group B (90 pieces B1 = 60, B2 = 30). Group A1 was used for naked eye observation, group A2 for MTT detection, group B1 for light microscope observation, group B2 for temperature detection in target area and irradiation area.
The irradiation power of FU was 200 W. The irradiation time was 5,10,20,30,60,90 s in group A and 30,60,90 s in group B.
The target area and the target area of the irradiated area were examined by naked eye, MTT staining, light microscopy and temperature detection. * the efficacy of focused ultrasound on porcine adipose tissue destruction and the dose reference for later vivo experiments were discussed.
2. live experiment part
Two pigs (weighing about 130-140 kg) were numbered A and B. Nine different doses of power (100,150,200) W and time (15,30,60) s were used in each experiment. Each dose acted at three different irradiation points, each time.
* pigs were selected as the irradiated area with thicker fat layer on both sides of abdominal wall. * a pig was selected for a experimentation area (36 irradiation points). * first days after the experiment, two pigs were selected on the left and right sides (36 on the left side, 36 on the right side), first days on the left side, and twenty-third days on the right side, and died on 30 days after the first experiment.
Blood lipids were detected before and after the experiment. The target area, irradiated area skin, important organs (heart and liver) were examined histologically. B * ultrasound was used to measure the thickness of fat layer in irradiated area before and after 2,7,23,30 days.
Result
1. in vitro experiments:
(1) No coagulative necrosis was detected by naked eyes and MTT (3-(4,5) -dimethylthiahiazo (-z-y1) -3,5-di-phenytetrazoliumromide (MTT) staining when the fat mass was irradiated by focused ultrasound for 5 s.
(2) At the time dose of 10,20,30,60,90 s, the volume of target necrosis and histological changes were observed. The temperature rise of the irradiated skin and target area was proportional to the irradiation time.
2. live experiment part:
(1) Gross observation: grey-white coagulative necrosis was found in the target area after irradiation with 200 W power and 30 s, 60 s irradiation time.
(2) Light Microscope (LM) observation: Hematoxylin-Eosin (HE) staining of target fat showed that FU had different destructive effects on subcutaneous adipose tissue of live pigs under different irradiation doses: when the energy was too low, the destructive effect of FU on subcutaneous fat was not obvious, when the given energy reached a certain threshold (200W), with irradiation. With the increase of irradiation time (< 60 s), the damage of the target area was more serious, and the vascular and nerve structures around the target area were intact.
(3) Electron Microscope (EM) observation: fibrosis and foam cells appeared in the target area after irradiation power of 200 W and irradiation time of 60 s.
(4) The thickness of subcutaneous fat in the irradiated area was decreased to some extent (P < 0.05) except 100W and 15s by B-mode ultrasonography. The thickness of subcutaneous fat in the irradiated area was decreased most obviously when the irradiated power was 200 W and 60s. There was no significant difference in the indexes of blood lipid between before and after the experiment (P 0.05).
Focused ultrasound can effectively destroy the subcutaneous fat of pigs without damage to the blood vessels and nerves around the target area. The experimental results show that the damage degree of the target area is obvious when the irradiation power is 200 W and the irradiation time is 30-60 s, which may be the best parameter for destroying the subcutaneous fat of pigs.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R310

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