骨折合并颅脑损伤大鼠血小板衍生生长因子表达的研究

Effect of traumatic brain injury on expression of platelet derived growth factors and fracture healing in rats

目的观察胫骨骨折合并颅脑损伤大鼠血清及骨痂组织内血小板衍生生长因子（PDGF）的表达变化，探讨颅脑损伤对骨折愈合的影响及作用机制。方法选择144只SD大鼠随机分为4组（n=36只）：正常对照组（N组）、颅脑损伤组（TBI组）、单纯骨折组（F组）和骨折合并颅脑损伤组（TBI＋F组），并制作相应组别的损伤模型。造模后第3天、1周、2周、3周、4周处死大鼠，4组均采用酶联免疫吸附试验法检测大鼠血清PDGF的表达；F组和TBI＋F组大鼠通过x线片观察右胫骨骨折处骨痂生长情况，通过苏木精．伊红染色观察骨痂生长及组织形态，免疫组织化学法检测骨痂组织PDGF的表达，逆转录聚合酶链反应法检测骨痂组织PDGFmRNA的水平，并进行比较。结果x线片示TBI＋F组大鼠骨折愈合速度比F组快。TBI＋F组大鼠血清PDGF表达量较其他3组高，且峰值时间提前，差异均有统计学意义（P〈0．05）。TBI＋F组大鼠骨折端局部成骨活动较F组强。TBI＋F组大鼠第3天、1周时局部骨痂组织中PDGF阳性细胞数较F组明显增多升高，且峰值时间提前，差异均有统计学意义（P〈0．05）。TBI＋F组大鼠第3天、1周时局部骨痂组织中PDGFmRNA表达水平较F组显著增高，差异均有统计学意义（P〈0．05）。结论颅脑损伤可以加速大鼠骨折愈合的进程，这可能与颅脑损伤后大鼠体内PDGF的表达增高有关。

Objective To explore the effect of traumatic brain injury on the fracture healing and its related mechanism by observing the expression of platelet-derived growth factors （PDGF） in serum and bone callus in rats with bone fracture and cerebral trauma. Methods One hundred and forty-four SD rats were randomized into 4 equal groups （ n = 36） which were subjected respectively to： no treatment （group N）, traumatic brain injury （group TBI）, bone fracture （group F） and bone fracture and cerebral trauma （group TBI ＋ F） . The animals were sacrificed at 3 days, l, 2, 3 and 4 weeks after modeling. In all the 4 groups, ELISA was used to detect the expression of PDGF in serum. In groups F and TBI ＋ F, the callus growth was observed at the fight tibial fracture site by X-ray, the callus growth and morphology were also observed by HE staining, the expression of PDGF in the callus tissue was measured by immunohistochemieal analysis, and the expression of PDGF mRNA in the callus tissue was measured by RT-PCR. Results X-ray showed that fracture healing was accelerated in group TBI ＋ F compared with group F. The serum expression of PDGF in group TBI ＋ F was significantly higher and the peak time was significantly earlier than in the other 3 groups （ P 〈 O. 05 ）. H-E staining showed that osteoblastic activity at the fracture ends in group TBI ＋ F Was stronger than in group F. Immunohistochemical staining showed that the expression of PDGF in the local callus was significantly higher at 3 days and 1 week in group TBI ＋ F and the peak time was significantly earlier than in group F （ P 〈 0. 05 ）. RT-PCR showed that the expression of PDGF mRNA in the local callus was significantly higher at 3 days and 1 week in group TBI ＋ F than in group F （ P 〈 0. 05 ）. Conclusions Traumatic brain injury can promote fracture healing in rats, which is probably related to increased expression of PDGF after cerebral trauma.