Objective: To investigate if the course of intervertebral disc degeneration (IDD) is delayed by injecting lentivirus (Lv) vector carrying bone morphogenetic protein 2 (BMP-2) and inhibitor of differentiation 1 (Id1) genes directly into the nucleus pulposus.
Methods: Thirty-two New Zealand white rabbits, 2.0-2.5 kg in weight and 4 months in age, were used to establish the IDD models at L 3, 4, L 4, 5, and L 5, 6 discs with annular puncture via transabdominal approach. Thirty rabbits with successful modeling were randomly divided into 5 groups, 6 rabbits every group. At 4 weeks after modeling, rabbits were injected with Lv-BMP-2 (group A), with Lv-BMP-2 and Lv-Id1 (group B), with Lv-Id1 (group C), with Lv-green fluorescent protein (group D), and with PBS (group E). At 2, 4, and 8 weeks after injection, T2-mapping MRI was performed on 2 rabbits each group to obtain the T2 values, and then subsequently the lumbar disc tissues were harvested to test the mRNA expressions and contents of collagen type II and proteoglycan by real-time fluorescent quantitative PCR and ELISA methods.
Results: T2-mapping MRI demonstrated that there was no significant difference in the T2 value between different groups at immediate and 2 weeks after injection ( P>0.05). The T2 value of groups A and B was significantly higher than that of groups C, D, and E at 4 weeks after injection ( P<0.05), but no significant difference was observed between group A and group B ( P>0.05). The T2 value of group B was significantly higher than that of the other groups at 8 weeks after injection ( P<0.05). The real-time fluorescent quantitative PCR and ELISA showed that the expressions and contents of collagen type II and proteoglycan in group B were significantly higher than those in the other groups at 2, 4, and 8 weeks after injection ( P<0.05).
Conclusion: Combined application of Lv-BMP-2 and Lv-Id1 can delay IDD changes in rabbit IDD models.
目的: 研究兔腰椎间盘髓核内注射慢病毒携带的 BMP-2 和细胞分化抑制因子 1（inhibitor of differentiation 1，Id1）基因能否有效改善椎间盘退变进程。.
方法: 取 4 月龄新西兰兔 32 只，体质量 2.0～2.5 kg；以 L 3、4、L 4、5、L 5、6 为目标椎间盘，经腹细针穿刺法制造椎间盘退变模型。将 30 只造模成功的实验动物随机分为 5 组，每组 6 只；造模后 4 周于各组目标椎间盘中分别注射 Lv-BMP-2 病毒（A 组）、Lv-BMP-2+Lv-Id1 病毒（B 组）、Lv-Id1 病毒（C 组）、Lv-绿色荧光蛋白空载体病毒（D 组）及 PBS（E 组）。于注射后 2、4、8 周各组分别随机取 2 只动物行 T2-mapping MRI 检查获得确切的T2弛豫时间（T2 值）；之后处死动物取椎间盘组织，应用实时荧光定量 PCR、ELISA 法检测 Ⅱ 型胶原及蛋白聚糖的 mRNA 相对表达量及含量。.
结果: T2-mapping MRI 检查示，注射后 0、2 周各组间 T2 值比较差异均无统计学意义（ P>0.05）；注射后 4 周，A、B 组 T2 值显著高于 C、D、E 组（ P<0.05），A、B 组间比较差异无统计学意义（ P>0.05）；注射后 8 周，B 组 T2 值显著高于其余各组（ P<0.05）。实时荧光定量 PCR 及 ELISA 检测示，注射后 2、4、8 周 B 组 Ⅱ 型胶原及蛋白聚糖的 mRNA 相对表达量及含量均显著高于其余各组（ P<0.05）。.
结论: 联合应用 BMP-2 和 Id1 基因在体内实验中能有效延缓兔腰椎间盘退变的进程。.
Keywords: Intervertebral disc degeneration; bone morphogenetic protein 2; gene therapy; inhibitor of differentiation 1.