Effects Of Radiofrequency Thermocoagulation On Chemonucleolysis With Collagenase In Vitro Experimental Study

Objective：to study the effects of Radiofrequency thermocoagulation on Chemonucleolysiswith collagenase by detection values of hydroxyproline and glycosaminoglycanabsorbance and observed the changes of pathological structural for lumbarintervertebral disc nucleus pulposusMethods：Nucleus pulposus tissue(weighted for1g) voluntcrily donated by24patientswith LDH and were collected with aseptic operation method,Then, The specimen ofnucleus pulposus were randomly assigned into4groups (n=6): Radiofrequencygroup (group I);collagenase group (group II); radiofrequency collagenase group(group III); the control group (group IV).Standard radio frequency for Group I(temperature90°C, the time120s×2), then Injection of saline0.3ml; injection ofcollagenase (50U,0.3ml) for group II;Given collagenase injection until thetemperature drops to below40°C after radiofrequency (RF parameters and dose ofcollagenase were unanimous with Group I and Group II) for group III; blank controlgroup (group IV) injection of saline0.3ml. All specimens in the sterile tube withsaline0.5ml (containing0.01mol/L CaC12),then Placed in a37°C incubator after24hours. the specimen was centrifuged, Measured by the spectrophotometer forvalue of hydroxyproline and proteoglycan in the supernatant, and the precipitate aftercentrifugation for histological pathological examination.Results：①The values of hydroxyproline absorbance for four groups were:0.096±0.021;0.549±0.021;0.314±0.112,0.087±0.040; the value of groupII and groupIIIwere higher than groupⅠ a nd groupⅣ (P <0.05),the value of group II was higher thangroupIII (P <0.05), while no significant difference between group I and group IV (P=0.86).②The values of hydroxyproline absorbance for four groups were:0.012±0.002;0.13±0.051;0.054±0.025;0.006±0.002.the value of groupII and groupIII were higher than group Ⅰa nd group Ⅳ(P <0.05),the value of group II was higher thangroupIII (P <0.05), while no significant difference between group I and groupIV(P=0．74).③Histological changes: Microscopic view of GROUPⅠshowing: Nucleuspulposus cells decreased, vacuolar degeneration, the arrangement of collagen fibers issparse; GroupⅡ: collagen fibers were dissolved basically by collagenase.onlyleaving the fiber mesh vacuolar structure,the stromal staining becameshallower.Microscopic view of GROUPⅢ showing: the deformation of the nucleuspulposus cells and spacing increases;the cells were significantly vacuolardegeneration; collagen fibers disordered. Nucleus pulposus for collagen fibernetwork becomes loose, there were uneven thickness and wavy collagenfibers.Collagen fibers fusiform, tapered fibrosis, a regular mesh structure disappeared;Cartilage cells scattered in the collagen fibers,showing multiple cell composed ofcartilage cells Island for GroupⅣ.Conclusion：The experiments comfirmed that:①Collagenase can dissolve the collagen fibers and raduce proteoglycan of theintervertebral disc;②solidification degeneration of the nucleus pulposus and contraction ofcollagen fibers after radiofrequency;③radiofrequency reduce the effect of collagenase on the dissolution of thenucleus pulposus.