| ObjectivesTo investigate the biological effect of high intensity focused ultrasound(HIFU) for lymphatic vessel of rat in different period.And providing a theoretical evidence for clinical application of HIFU for the treatment of chyluria.Methods1.According to the different observational time,the 32 SD rats were randomly and equally divided into 4 groups,each group contains 8 rats.The right inguinal region of each rat was irradiated using HIFU and the left side was self-control.2.The rats were anesthetized using Chloral Hydrate by peritoneal injection and the right inguinal regions were depilated and cleaned.The rats were fixed in a supine position on the home-made hob which was putted over the ultrasound source and the buttocks of rats must be immersed in de-aerated water.Then we identified the right inguinal area at the junction of the hind limbs and trunk as the target area of HIFU through B-probe on the machine.3.The technical parameters of HIFU:Focal region:3mm×3mm×8mm,Power of ultrasound:300W,Irradiation time of one point:0.15s,Interval time of one point: 0.18s,Irradiation times of one point:50,Total irradiation time:15 minutes.The rats were irradiated once a day,for two consecutive days,then dissected within 24 hours, 72 hours,7 days and 30 days after irradiation and we observed the macroscopic changes of two side areas.Then we took a piece of inguinal neurovascular bundle and surrounding tissue at the junction of the hind limbs and trunk.The tissue size was 1.0cm×0.8cm×0.4cm and we intersected it into the same two specimens,one for frozen section,the other for preemergency.At the same time,we took a piece of spleen tissue using as positive control of immunohistochemistry.The three tissue specimens were wrapped by normal saline gauze and preserved in ultra-low temperature of-80℃refrigerator in order to slice at the same time.4.The three frozen sections of each specimen were serial.The thickness was 5μm,one for HE stain,another for immunohistochemistry stain and the third for negative control.We choose the spleen tissue as positive control according to the reagent description.5.When we observed the changes of the specimens using HE stain and immunohistochemistry stain,we observed its ultrastructure changes by transmission electron microscope using the backup specimen.Results1.HIFU penetrated the skin and precisely damaged lymphatic vessels.Compared to control sides,we could see hyperemia,edema,inflammatory cell infiltration and the lymphatic vessels rupture,deformation and so on in the experimental sides of 24h group and 72h group.The experimental sides of 7d group and 30d group were seen decrease in the number of lymphatic vessels,lumen occlusion,scar formation around the lumen and so on.The arterial and venous vascular had no significant injury changes at the same part.2.After the irradiation of HIFU,the LVD of experimental side significantly decreased compared with the self-control side in all groups.(P＜0.01)3.After the irradiation of HIFU,the LVD of experimental side significantly decreased with the time going.(P＜0.01) The decrease of LVD was not significantly between 7d group and 30d group.(P＞0.05)ConclusionThe inguinal lymphatic vessel can be directed injured by HIFU,being seen rupture and decrease in the number of lymphatic vessels,lumen occlusion,scar formation around the lumen and so on,but it is safe for great blood vessels. |
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