The Study On Physical Characteristics Of Radial Extracorporeal Shock Wave And Its Effect On Biological Characteristics Of Chondrocytes And Pre-chondrocytes

[Backgrounds]With the popularization of nationwide fitness campaign, exercise systemdamage is showing a rising trend year by year, with a high incidence of articularcartilage injury, we study2479of patients with knee surgery epidemiologicaldistribution[1], in which the articular cartilage injury account for55.1%, the rangeof age distribution is large, the young and middle-aged is the main crowd, gendercomposition is similar. Articular cartilage injury often lead to joint pain,movement disorder, more seriously, it can cause the loss of joint function, as theimportant cause of physical disability[2-4]. Currently, clinical commonly used andeffective method is micro fractures with arthroscope, by stimulating generation ofthe bone marrow mesenchymal stem cells (BMSCs) to repair cartilage. whereas,the result mostly is fibrous tissue, whose compressive strength is worse than thenormal cartilage; Because of the expensive cost, long cycle and narrowapplication of tissue engineering, cartilage repairation is still the most intractableproblem in clinical. In the early period of the study, the micro fractures combiningwith shock wave in the articular cavity repair the distal femoral cartilage defect,the result indicates the formation of something like transparent cartilage, thismethod is better than micro fractures only[5]. Laboratory studies have shown thatrESWT has repair effect on cartilage injuries[6], Clinical studies have also shown that rESWT have definite effect on lateral epicondylitis, supraspinatuscalcification, Achilles tendinitis, soft tissue injuries, relief of chronic pains and soon[7]. There exists many and complex impact indicators In clinical application forrESWT, we lack a unified indicator to measure and evaluate their effects. We willface various difficulties, which have no relate studies to solve these problems athome and abroad, such as which kind of shock wave transmitters we use, pressureand frequency of symptomatic therapy in the clinical to achieve the best results[8].[Aims]Explore the unified index about the effect of rESWT, study preliminarily thebiological effect of Chondrocytes and Pre-chondrocytes by rESWT stimulationand provide experimental evidence about the best way to use rESWT repairingcartilage damage for further study.[Materials and Method]We use divergent wave instrument to test two standard transmitters,15mmand6mm of diameter, observing the two transmitters at different pressures and theoutput energy change rule when the frequency changes. According to the schlierenimaging system, We observe the output waveforms in the shock wave instrumentwith the high-speed data acquisition instrument, separately with the Planar impacttransmitters of36mm, standard treatment transmitters of15mm, standardtreatment transmitters of10mm, elongated treatment transmitters of15mm, at thepressures of2×105Pa,3×105Pa,4×105Pa, frequency of10Hz. We will observethe spread from of shock wave and work range in air, with different transmitters ofrESWT at different pressures.We will separate knee joint cartilage to chondrocytes and pre-chondrocytesby using the New Zealand white rabbit. After training to second passage, usingstimulation of rESWT impacting600times, at the pressure of0.8×105Pa,1.5×105Pa,2.5×105Pa,3.5×105Pa, frequency of10Hz, We will observe the differences inproliferation cells after24h rESWT stimulation, using the experimental group ofthe highest proliferation activity to next experiment under pressure stimulation, and observe differentiation changes in the three lines of cells with histochemicalstaining, test related mRNA levels of Cartilage differentiation in the two cellsWith Q-PCR after stimulation.[Result]We found significant difference (P<0.05) at the same frequency, differentpressures with the measurement of outgoing energy of rESWT. There is also asignificant difference (P<0.05) when the situations are the same pressure, differentfrequencies. At a low pressure (0.5×105Pa,1.0×105Pa), the energy of individualpulse will rise when the frequency increases; However, when the pressure(2.0×105Pa,3.5×105Pa) increases, the energy of individual pulse is graduallydeclining when the frequency increases. As the pressure increases, the energy ofindividual pulse at each frequency is increased, the higher the frequency, thesmaller the increasing rate. As the pressure increases, the same shock wavetransmitters’s work distance also becomes long. The operating distance of shockwave in air from far to near is,36mm planar transmitters>15mm elongatedtreatment transmitters>10mm standard treatment head>15mm standard treatmenthead.15mm long transmitters has longer range and greater operating range angle,compared to the15mm standard transmitters.After24h stimulation of chondrocytes and pre-chondrocytes, theproliferative activity by CCK-8show that after the stimulation both the two kindsof cell proliferation activity are increased (P<0.05). Histochemical staining resultscan show that chondrocytes differentiation ability is not obvious, whereas,pre-chondrocytes after shock wave stimulation and induction, has the strongability of differentiation. The result of Q-PCR testing related mRNA levels inchondrocytes showed that whether the cartilage cells are differentiation inductionor not,1.5×105Pa rESWT stimulation group could significantly increases theexpression levels of cartilage differentiation related genes (P<0.05),andpre-chondrocytes has higher expression levels of the associated genes than that ofchondrocytes(P <0.05). [Conclusion]This study proposes a method for measuring the output energy of rESWT,which is beneficial to the more accurate research the mechanism of shock waverepairing cartilage damage. In the process of repairing cartilage damage, shockwaves can promote the repairation of cartilage damage, instead of chondrocytes,Pre-chondrocytes may play a more important role in the process.