跟腱创伤伴随颅脑损伤后跟腱异位骨化机制研究

Study of heterotopic ossification induced by Achilles’tenotomy combined with traumatic brain injury

目的探讨跟腱创伤伴随颅脑损伤后跟腱异位骨化发生的机制。方法选取42只雄性SD大鼠,采用随机数字表法将其随机分为3组,其中,空白对照组6只,跟腱创伤组(HO组)18只,跟腱创伤伴随颅脑损伤组(TBI组)18只。在造模后1、2、4周,通过micro-CT比较HO组、TBI组大鼠跟腱局部开始出现异位骨化的时间、异位骨化的骨密度(BMD)及骨体积占比(BV/TV);通过苏木素伊红染色比较异位骨化的骨小梁厚度(Tb.Th);通过免疫组化检测跟腱创伤局部的焦亡相关蛋白的表达水平;通过透射电镜(TEM)检测HO组、TBI组大鼠跟腱局部早期的病理性矿化。结果TBI组大鼠出现异位骨化的时间早于HO组,且造模4周后,TBI组的BMD及BV/TV均大于HO组,差异有统计学意义(P<0.05);同时,TBI组大鼠异位骨化的Tb.Th也大于HO组,差异有统计学意义(P<0.05)。在造模1周后,TBI组损伤跟腱组织中的NLRP3^(+)、CASPASE-1^(+)、GSDMD^(+)的细胞均高于HO组,差异均有统计学意义(P<0.05)。同时,造模1周后,TBI组跟腱创伤局部钙磷沉积含量显著高于HO组。结论颅脑损伤显著加速跟腱创伤局部异位骨化进程,其机制可能与细胞焦亡提高局部炎症水平加重异位骨化的发生相关。

Objective To explore the mechanism of heterotopic ossification(HO)induced by achillotenotomy concomitant with traumatic brain injury(TBI).Methods A total of 42 male SD rats were selected and randomly divided into 3 groups by random number table method,including 6 blank control group,18 Achilles tendon trauma group(HO group)and 18 Achilles tendon trauma with craniobrain injury group(TBI group).Micro-CT was used to compare the time of local ectopic ossification,bone mineral density(BMD)and bone volume/tissue volume(BV/TV)of HO group and TBI group at 1,2 and 4 weeks after the model.The trabecular thickness(Tb.Th)of ectopic ossification was compared by hematoxylin eosin(HE)staining.Immunohistochemistry was used to detect the expression level of pyrodeath related proteins in Achilles tendon trauma.Early local pathological mineralization of Achilles tendon in HO and TBI groups was detected by transmission electron microscopy(TEM).Results The time of ectopic ossification in TBI group was earlier than that in HO group,and BMD and BV/TV in TBI group were higher than those in HO group 4 weeks after modeling,the difference was statistically significant(P<0.05).At the same time,the Tb.Th of ectopic ossification in TBI group was higher than that in HO group,and the difference was statistically significant(P<0.05).After 1 week of modeling,NLRP3^(+),CASPASE-1^(+) and GSDMD^(+) cells in TBI group were higher than those in HO group,with statistical significance(P<0.05).At the same time,the content of calcium and phosphorus deposition in TBI group was significantly higher than that in HO group after 1 week of modeling.Conclusion TBI significantly aggravates the process of heterotopic ossification in the injured achilles tendon.The mechanism is referred to pyroptosis which implicated in aggravating calcification process in HO by increasing the level of local inflammation.