The Histomorphological Research Of Adolescent Age Rabbit Cervical Vertebra Growth Cartilage Separation Injury

Adolescent vertebra was on the stage of maturing,and the growth cartilage of endplate is the most weak part of vertebra motion unit. It can be brokened easily by the level shearing force. Expectant treatment was main measure to this kind injury,but the patient was young, complication was universal,ep:vertebra development malformation,intervertebral disc degeneration,and vertebral degeneration. whether it should be treated on the early stage,it is a problem. This experiment want to make a model of adolescent age rabbit cervical vertebra growth cartilage separation injury,without any treatment,and view the injury can heal or not,appraise the influence it bring to the disc and periphery tissue. Try to give a support to clinic.ObjectiveTo view whether adolescent age rabbit cervical vertebra growth cartilage separation injury can heal, and appraisal the change of peripheral histomorphology after the injury.Material And Methods1,Experimental animal: 2.5month-old 32 healthy male New Zealand white rabbits were divided into two groups, model group and control group. Provided by Zhejiang province academy of medical science.2,Drugs and equipments: conventional animal surgical instruments, 2 ophthalmology histoclippers,2 ophthalmology plyers,2 miniretractor,1 bone hook; Iodophor,75% alcohol,3% pentobarbital, 10% gentamycin, atropine, normal sodium.3,Method: Weighing, intravenous anesthesia with 30mg/kg pentobarbital, intramuscular injection 1ml atropine preoperative. Fix the animal on the operation table,prepare the skin, degerming and spread the surgical drape. Model group:An experimental model of 5th and 6th cervical vertebra growth chondrodialysis injury in rabbits was established. Control group:cutdown the skin and fascia. It was evaluated histomorphologically that whether the injury can healing. The thickness of the calcified layer and the uncalcified layer of the cartilage endplate was measured in each degenerated cervical disc. Grading the degree of intervertebral disc degeneration accord to the Miyamoto methods. The height of the intervertebral disc was measured in each experimental animal. Student' s t test was used to compare the average thickness of calcified layer of the cartilage endplate and the height of the intervertebral disc in each experimental animal.Results All the animal survived,and the animal model succeeded .Growth cartilage malunion after 6 weeks compared with control group histomorphologically. The model group's articular cartilage calcification layers are thicker than control group conspicuously on the related time points(P<0.05) .Nucleus pulposus and annular fibrosus degenerated conspicuously on the 6weeks,and nucleus pulpsuses are replaced by the chondroid tissue. A positive correlation existed between the thickness of the calcified layer of the cartilage endplate and the degree of the cervical disc degeneration( r = 0.92). The later of the experiment time,the lower of model group's intervertebral disc height(P<0.05),and model group's intervertebral disc height is lower noticeably than control group's.ConclusionAdolescent age rabbit cervical vertebra growth cartilage separation can malunion itself, but accelerated intervertebral disk's degeneration, and the calcification of the articular cartilage could initiate and promote intervertebral disc degeneration.