| BackgroundAcnsitizaupoint setion refers to the transformation of acupoints from resting state in physiological state to activating state in pathological state,so as to realize the function of receiving stimulation and regulating body state.The "sensitized acupoints" as a reflection site of disease on the body surface also have important clinical value.At present,the research on acupoint sensitization focuses on acupoint photosensitization,electrosensitization,thermal sensitization and microcirculation sensitization.As an important structure of human organs,microcirculation plays a key role in material supply and metabolism,maintaining blood perfusion and internal environment stability,and is closely related to acupoint sensitization.The microcirculation sensitization of acupoints is mainly manifested in the state of disease,and the local microcirculation flow and vascular permeability of specific acupoints are significantly changed.At present,the imaging research of acupoint sensitization at the level of tissue microcirculation is relatively inadequate.Not only the imaging technology lags behind seriously,but also its specificity and accuracy are at a low level,which restricts the in-depth study of acupoint sensitization to a certain extent.Photoacoustic imaging(PAI)is a new generation of advanced international imaging technology.It has high contrast of optical imaging and is sensitive to tissue functional characteristics.At the same time,it has high detection depth and good spatial resolution of deep tissue.It has advantages of non-destructive,living,real-time,functional and cross-scale.This technique can achieve subcutaneous microcirculation imaging at capillary level in a certain depth range and quantitatively evaluate its structure and morphology,showing great advantages in the field of microcirculation imaging.Therefore,in this study,PAI technology is used as a research tool to study acupoint sensitization,in order to present the characteristic change of acupoint sensitization process-the morphological structure and functional state of local microcirculation blood vessels,so as to reveal the connotation of acupoints and explore the basic law of acupoint sensitization,so as to provide objective basis for clinical acupuncture and moxibustion.PurposesThe morphological changes of local microvasculature in Zusanli,Yanglingquan and non-acupoints of knee osteoarthritis mice from physiological resting state to pathological sensitization state were elucidated by photoacoustic imaging technology,and the specific connotation of acupoint sensitization in the structure of tissue microcirculation was preliminarily explained.MethodsIn this study,12 SPF BALB/c mice aged 8 weeks were selected and fed for 1 week.They were randomly divided into three groups:control group,Knee Osteoarthritis Model(KOA)and False Model(FM),with 4 mice in each group.The KOA model of mice was prepared by injecting monoiodoacetate(MIA)into knee joint on day 0.Specific methods are as follows:0.9%sterile saline was used to prepare MIA solution with concentration of 0.05 mg/mu L.After intraperitoneal injection of sodium pentobarbital(1%,30 mg/kg),the mice were anesthetized,and the hairs near the knee joint of the right hind limb were cleared.After the joint was flexed to the maximum extent,the MIA solution of10 mu L was injected into the knee joint cavity through the lateral knee patellar ligament of the right hind limb of the mice with 27G sterile syringe.In FM group,10 mu L 0.9%saline was injected into the knee joint cavity of the right hind limb by the same method,while in Control group,no treatment was done.Detection methods and indicators:On day 0,7 and 21,PAI system was used to monitor the microcirculatory vascular curvature,diameter percentage and density of right hind limb Zusanli,Yanglingquan and non-acupoint areas of mice in each group.Micro vascular quantification algorthm(MVQA)was used to analyze data in Matlab software.On the 21st day of the experiment,the mice in each group were killed by intraperitoneal injection of pentobarbital(150 mg/kg).The right knee joint was stained with safranine and fixed green.The histomorphological changes of knee joint were observed under light microscope.Results1.Observation of Safranine Fixed Green Staining SectionOn the 21st day of the experiment,the cartilage matrix of control group was uniformly red with clear tidal line,while the cartilage surface of FM group was smooth,the chondrocyte was arranged neatly,and the cartilage layer was uniformly red stained with saffron.The cartilage of control group and FM group showed no damage and the cartilage morphology was intact.In KOA group,the thickness of articular cartilage became thinner,the arrangement of cells was disordered,the matrix of cartilage erosion was lost,the cartilage fissures were more,the staining was light and uneven,the surface layer of cartilage was denuded and deformed,and the middle layer cyst was formed.2.Quantitative analysis of PIA chart and microcirculation structure in Zusanli,Yanglingquan and non-acupoint areas2.1 Microvascular Curvature ResultsOn day 0,7 and 21,PAI system showed that there was no significant difference in microvascular curvature between K OA group and Control group(P>0.05),and between Control group and FM group(P>0.05)2.2 Percentage of microvessel diameterThe diameter of microvessels ranges from 10 to 100 micrometers,and the local diameter ranges from 20 to 60 micrometers in Zusanli,Yanglingquan and non-acupoints.On day 0,7 and 21,PAI system showed that there was no significant difference in the percentage of microvessel diameter between KOA group and Control group(P>0.05),KOA group and FM group(P>0.05).2.3 Microvessel Density ResultsOn day 0,7 and 21,PAI system showed that there was no significant difference in microvessel density between KOA group and Control group(P>0.05),KOA group and FM group(P>0.05).Conclusion(1)The PAI results showed that the microvascular curvature,diameter percentage and density of Zusanli,Yanglingquan and non-acupoints in blank group,knee osteoarthritis model group and sham model group did not change significantly(P>0.05).The results suggest that the local microcirculation structure of acupoints and non-acupoints has not changed under acupoint sensitization.(2)Under the condition of KOA disease,the local microcirculation structure of Yanglingquan and Zusanli,commonly used acupoints,has no obvious change.The important connotation of acupoint sensitization may be the change of microcirculation function,not the change of morphological structure.(3)This study is the first time to apply PAI technology to the study of local micro vascular morphological changes of acupoints under acupoint sensitization.It is not only a major breakthrough in the study of acupoint in vivo imaging,but also lays a scientific foundation for the study of real-time high-resolution imaging of acupoint sensitization. |
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