| As a common, high incidence, and tough clinic disease, lumbago affected the work and life of patients seriously. Recently the incidence of discogenic low back pain is increasing, become the hot field of the current low back pain research. Lumbar discogenic pain, LDP, refers to pain originated from the disc itself, the typical symptoms are Lumbar pain, hip pain, lumbago and groin widespread pain. This is very similar with the Chinese medicine described in the "Belt Vessel stasis pain"--"the typical manifestations of abdominal pain in the lumbar spine, spreading to the groin". Besides tenderness during spinous processes, abnormal palpable is found that except interspinous tenderness, also has the iliopsoas muscle spasm and pain, tension, especially the psoas major muscle, this type of low back pain not only has the disc itself pathological changes, pathological changes may be accompanied by para spinal muscle. Plucking psoas major muscle can alleviate lumbago clinically. Explaining it in the theory of spine stability, we think the lumbago is usually caused by disorder both spinal static structures and dynamic structures, and intervention to para spinal muscles, the dynamic structure, may promote the repair of interverterbral disc, the static structure.OBJECTIVEThe current experiment established lumbar intervertebral disc injury rat model by needle stabbing, observing if there are morphological and passive mechanic changes in psoas major muscles, if psoas major plucking will affect these changes, and explain the mechanism of psoas major plucking on discogenic low back pain.METHODExperiment1:Male Wistar rats, aged7weeks (n=30), were randomly divided into operation group (n=20) and sham operation group (n=10). Anterior fiber ring full-thickness needling injury to L4-5, L5-6disc, were operated in the model rats, making disc injury model. Sham operation group disc without needle injury operation. To the disc modelling operation, the modeling rats were randomly divided into model group and treatment group.2weeks after modelling operation. The rats of treatment group were placed into the rat bag, in prone posture, plucking bilateral psoas major muscle, one time per other day,10times in total (about3weeks). The rats of model group and sham operation group only bagged, no treating.In order to observe the change of behavior performance after modeling, open field test were used to examine animals’vertical activity. Before modelling operation,10rats were randomly selected to observe the vertical activity.2weeks after modelling operation, the vertical activity were observed for sham operation group and model group. After10times treatment, the sham operation group, model group and treatment group were observed.After10times treatment, all rats were euthanized. Bilateral psoas major muscles were collected to test the passive tensile. And L4-5, L5.6interverterbral discs were used for HE staining and IL-1β immunohistochemical method testing the positive expression of inflammating factor IL-1β in the intervertebral disc.Experiment2:Male Wistar rats, aged7weeks (n=8), were randomly divided into model group (n=6) and sham operation group (n=2). After the same modelling operation. Then the model group rats were randomly divided into1week,3weeks,6weeks model group (n=2, each group). And taken out of the bilateral psoas after operation in1week,3weeks,6weeks respectively.Psoas muscle HE staining was done, to observe the morphological changes. Picric acid Sirius red staining was done, to observe the nature and content of collagen in psoas major muscle.RESULTS1Vertical activity detection:5weeks after modelling operation:compared with the sham operation group, infrared count of vertical activity in the model group was decreased, and the difference was statistically significant (P<0.05). Compared with the model group, vertical stand infrared counts of the treatment group increased, but the difference was not statistically significant (P>0.05). It shows rats standing upright activity was decreased5weeks after intervertebral disc injury.2Disc HE staining:5weeks after modelling operation:nucleus pulposus:sham operation group show the central intensived even distributed, around the present state of uniform distribution, with a large number of nucleus pulposus cells; the nucleus of model group show sparse, unevenly distribution, with a large number of amorphous substances; treatment group was similar to the sham operation group. Fiber ring:sham operation group show ordered fibrous ring, the nucleus was clear; model group with slightly changed in the arrangement of fiber ring, with a disorder tendency; the fiber ring shape of the treatment group was similar to the sham operation group. It suggested that needling injury of fiber ring can cause a certain extent of damage of the intervertebral disc, plucking psoas muscle therapy may have a good effect on the intervertebral disc anulus fibrosus injury.3Disc IL-lp immunohistochemistry:Annulus fibrosus cells showed the positive expression of intervertebral disc inflammation factor IL-ip, positive cells were brown. The differences of positive immunohistochemical expression of integral optical density (IOD) between the three group have statistically significant (P<0.05); compared with the sham operation group, IOD of model group positive expression of IL-1β was significantly increased (P<0.01); compared with the model group, the treatment group positive expression of IOD decreased obviously, the difference has statistical significance (P<0.01). It is suggested that needling injury fiber ring will cause an inflammatory response, and plucking psoas muscle therapy will have a good effect to the intervertebral disc inflammation.4Tensile of psoas major muscle:Elastic modulus comparision between left psoas muscle:there was no significant difference between the three groups (P>0.05). Elastic modulus contrast between right psoas major muscle:there have a significant difference between the three groups (P<0.05). Compared with the sham operation group, the model group reduced significantly, the difference was statistically significant (P<0.01); compared with the model group, the treatment group increased slightly, but the difference was not statistically significant (P>0.05). It is suggested that, after injurying intervertebral disc anulus fibrosus, the elastic modulus of right psoas muscle have decreases to a certain extent, plucking psoas muscle treatment may has certain intervention effect to the elastic modulus of psoas muscle.5Psoas muscle HE staining:1weeks after modelling operation, we find that the psoas muscle fibre bundles arrange orderly, closely, including muscle nuclear oval, lie along the long axis the edge of the muscle fiber, a few muscle nucleus located within the muscle fibers.3weeks after modelling operation, the psoas muscle fibers appeared degeneration, the muscle fibers appears mild swelling, muscle striations fuzzy, sarcoplasmic showed villous or fusion change.6weeks after modelling operation, the muscle fiber degeneration aggravating, muscle striations blurred or disappeared, eosinophils increased, sarcoplasmic villous or fusion change obviously, muscle fiber disordered, and even appeared segment degeneration.6Picric acid Sirius red stainingCompared with the sham operation group, the intramuscular collagen content of psoas in model group have a certain degree of change.CONCLUSION1Changes of vertical stand infrared counter, intervertebral disc morphology, inflammatory factor IL-1β of intervertebral disc and psoas major muscle tensile mechanical properties, psoas major muscle morphology, indicate that all intervertebral disc injury can cause a certain degree of changes in elastic modulus of psoas muscle.2After plucking psoas major muscle treatment, elastic modulus of psoas major muscle in the intervertebral disc injury rat model has been restored, and morphology of intervertebral disc, factor expression of IL-1β get ameliorated. |
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