转化生长因子β2在兔退行性变椎间盘纤维环中的表达

Expression of transforming growth factor beta 2 in fibrous rings of degenerative intervertebral disc of rabbits

目的:观察转化生长因子β2在兔椎间盘退行性变过程中的表达情况并探讨其意义。方法:实验于2005-03/2006-01在协和医院骨科实验室进行,手术后动物饲养于协和医院实验动物房。标本的免疫组织化学及蛋白免疫印迹检测在同济医学院免疫学教研组实验室完成。①健康4个月龄雌性日本大白兔12只,采用随机数字法分为假手术组3只、椎间盘退变模型组9只。构建前路纤维环损伤致兔椎间盘退变模型。②于造模的第1,2,4周采用Thompson评分评价椎间盘退变程度。③采用免疫组织化学法检测纤维环内转化生长因子β2分布情况。④采用反转录-聚合酶链反应检测转化生长因子β2基因表达情况。结果:12只兔均进入结果分析。①兔椎间盘退行性变程度评价:根据Thompson分级法,假手术组3只均为Ⅰ级,模型组第1周2只为Ⅱ级,1只为Ⅲ级,第2周3只均为Ⅲ,第4周3只均为Ⅳ级。椎间盘退行性变程度随着造模时间的延长而加重。②各组大鼠椎间盘标本免疫组织化学结果:假手术组及造模1,2及4周纤维环内转化生长因子β2染色阳性细胞率分别为73.2%,35.7%,19.6%及3.7%,造模第4周组明显低于假手术组(P<0.01)。③各组大鼠转化生长因子β2反转录-聚合酶链反应检测结果:转化生长因子β2基因的表达随着造模时间的延长而逐渐减弱,造模第4周组较假手术组下降最为明显。结论:转化生长因子β2在椎间盘内的含量及表达随着椎间盘退行性变程度的加剧而下降,这种下降可能是椎间盘的退行性变机制之一。

AIM： To observe the expression of transforming growth factor （TGF） β2 in degeneration of rabbits＇ intervertebral disc and its significance. METHODS： The experiment was conducted from March 2005 to January 2006 in the Laboratory of Department of Orthopaedics, Union Hospital, breeding in ped of Union Hospital. Immunohistochemistry and proteinum immunization blotting were finished in Laboratory of Department of Immunology, Tongji Medical College. ①A total of 12 healthy Japanese white female rabbits aged 4 months were selected. They were divided into sham operation group with 3 rabbits, intervertebral disc degeneration model group with 9 rabbits. Intervertebral disc degeneration models induced by anterior fibrous ring injury were established. ②Degree of intervertebral disc degeneration was evaluated with Thompson at weeks 1, 2 and 4 after establishing models. ③Distribution of TGFβ2 in fibrous rings were examined with immunohistochemical method.④The expression of TGF β2 was measured with reverse transcription-polymerase chain reaction （RTPGR）. RESULTS： Totally 12 rabbits were involved in the result analysis. ①Evaluation of degree of intervertebral disc degeneration of rabbits： According to the Thompson, the 3 rabbits in the sham operation were in grade Ⅰ ; In the model group 2 rabbits were in grade Ⅱ and Ⅰ rabbit in grade HI at week 1; the 3 rabbits were all in grade Ⅲ at week 2, and all in grade Ⅳ at week 4. The intervertebral disc degeneration became severe with the prolongation of establishing models. ② Result of immunohistochemistry in rats of each group： Positive cell rates of TGF β2 in fibrous rings at week 1, 2 and 4 and in the sham operation group were 73.2%,35.7%, 19.6% and 3.7%, respectively. It was lower obviously at week 4 group than that in the sham operation group （P 〈 0.01 ）. ③Result of RT-PCR in TGF β2 in rats of each group： The expression of TGF β2 was less with the prolongation of establishing models, especially at week 4 group as compared with the sham operation group. CONCLUSION： TGF β2 in intervertebral disc descends with the disc degeneration. This may be one of the mechanisms in the disc degeneration.