丝素蛋白多孔支架在大鼠脊髓血管化中的实验研究

目的观察丝素蛋白多孔支架(Porous Silk Fibroin Scaffolds,PSFSs)在大鼠脊髓损伤部位的血管化,为丝素蛋白材料用于组织工程修复中枢神经损伤提供实验依据。方法制备具有一定孔径和孔隙率的PSFSs;选取28只清洁级雌性S-D大鼠(体重250~300g),随机分为A、B两组(A为实验组,n=16;B为对照组,n=12)。建立脊髓半横断损伤模型,实验组植入PSFSs,对照组植入聚乙烯醇(Polyvinyl Alcohol,PVA)海绵。术后4、7、10、14、21、28d,每组各取两只大鼠灌注取材行组织学、免疫组织化学(CD34)检测,并采用透射电镜观察A组微血管超微结构。结果 HE染色示A组炎症反应较B组轻、消退速度快;PSFSs降解速度比PVA快;通过CD34染色计数材料内微血管密度(MVD),A组在术后7、10、14、21、28d分别为1.4、3.6、10.6、8.6、8.8,对照组分别为0、2.2、4.8、4.6、4.0,差异具有统计学意义(P<0.05)。A组在术后7d即可观察到材料内有微血管形成,14d时达到峰值,随后有所下降并稳定于一定水平;B组7d时尚无微血管形成,14d时微血管数量较多,也呈现有所下降并趋于稳定的变化规律。结论 PSFSs能在大鼠脊髓内血管化,可用于神经组织工程支架修复中枢神经损伤。

Vasculaerization of porous silk fibroin scaffolds following spinal cord injury in rats

Objective To observe the vascularization of porous silk fibrion scaffolds(PSFSs) following spinal cord injuries in rats so as to lay the foundation for the application of PSFSs in tissue engineering. Methods PSFSs were prepared with certain pore sizes and porosity.28 female Sprague-Dawley rats,250~300g in body weight,were selected and devided into two groups(A:experimental group,n=16;B:control group,n=12). All the animals received an operation of semi-transection in spinal cord.PSFSs were transplanted in animals in A group while other animals in B group received Polyvinyl Alcohol(PVA). After a survival period of 4~28 days,rats were killed following a perfusion,the spinal cords including materials were cut for histological and immunohistological staining. Furthermore,the unltrastructure of microvessels was detected with TEM in A group. Results HE staining shows that the inflammatory response was more moderate in A group than that in B group,and the degradation of materials was more obvious in A group than that in B group. MVD at 7d,10d,14d,21d,28d postoperation in A group was 1.4,3.6,10.6,8.6,8.8,respectively. On the contrary,the quantity in B group was 0,2.2,4.8,4.6,4.0. The microvessels in A group were observed even at 7d postoperation,and the peak appeared at 14d postoperation. Then the quantity decreased to a stable level. The trend of MVD in B group was similar to that in A group. Conclusion PSFSs can be vascularized in spinal cord of rats,and it can be applied for nerve tissue repair in tissue engineering.