Modelling neurofibromatosis type 1 tibial dysplasia and its treatment with lovastatin.
Modelling neurofibromatosis type 1 tibial dysplasia and its treatment with lovastatin.
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建模神经纤维瘤病1型胫骨发育不良及其用洛伐他汀治疗。
DOI：
10.1186/1741-7015-6-21
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发表时间：
2008-07-31
期刊：
影响因子：
9.3
通讯作者：
Mundlos, Stefan
中科院分区：
文献类型：
--
作者：
Kolanczyk, Mateusz;Kuehnisch, Jirko;Kossler, Nadine;Osswald, Monika;Stumpp, Sabine;Thurisch, Boris;Kornak, Uwe;Mundlos, Stefan
胫骨弯曲和/或假关节是 1 型神经纤维瘤病 (NF1) 已知的严重并发症。发育中的四肢和颅骨 (Nf1Prx1) 中神经纤维蛋白 (Nf1) 条件失活的小鼠表现出由于骨矿化减少和骨血管化增加导致的胫骨弯曲。然而，与 NF1 患者相比，Nf1Prx1 小鼠不会发生自发性骨折，这可能是由于机械负荷相对较低。我们研究了 Nf1Prx1 小鼠皮质骨损伤模型中的骨愈合情况，作为 NF1 相关骨病的模型。利用这个实验模型，我们探索了全身应用洛伐他汀（一种降胆固醇药物）对 Nf1 缺陷骨修复的影响。根据先前描述的方法，在 Nf1Prx1 突变小鼠和同窝对照小鼠的胫骨结节中诱导双侧皮质损伤。对每只动物的石蜡和甲基丙烯酸酯切片进行分析。我们将 24 只性别匹配的突变小鼠分为洛伐他汀治疗组和未治疗组。洛伐他汀治疗的小鼠每天灌胃0.15毫克活化洛伐他汀。使用组织学方法、显微计算机断层扫描测量和原位杂交在损伤后的三个连续时间点对骨修复过程进行分析。在每个实验时间点，分析三只洛伐他汀治疗的突变小鼠、三只未治疗的突变小鼠和三只未治疗的对照小鼠。受伤后第 14 天被人道处死的动物组扩大到六只经过治疗的突变小鼠和六只未经治疗的突变小鼠以及六只对照小鼠。骨损伤修复是一个复杂的过程，需要多种细胞类型的共同努力。它是由炎症反应引发的，炎症反应刺激周围结缔组织的成纤维细胞增殖并用临时细胞外基质填充损伤部位。与此同时，来自骨膜的间充质祖细胞被募集到损伤部位，成为成骨细胞。在 Nf1Prx1 小鼠中，骨修复被延迟，其特征是纤维软骨组织的过度形成和持续存在以及细胞外基质矿化受损。相应地，Runx2的表达下调。高剂量全身洛伐他汀治疗可恢复 Runx2 表达并加速新骨形成，从而改善 Nf1Prx1 胫骨的皮质骨修复。骨合成代谢效应与 Nf1 缺陷细胞中丝裂原激活蛋白激酶途径过度激活的减少相关。我们的数据表明洛伐他汀（美国食品和药物管理局于 1987 年批准用于治疗高胆固醇血症的药物）在治疗 Nf1 相关骨折愈合异常方面具有潜在用途。这里提出的实验模型构成了针对 Nf1 相关骨发育不良的候选药物临床前阶段测试的宝贵工具。
Bowing and/or pseudarthrosis of the tibia is a known severe complication of neurofibromatosis type 1 (NF1). Mice with conditionally inactivated neurofibromin (Nf1) in the developing limbs and cranium (Nf1Prx1) show bowing of the tibia caused by decreased bone mineralisation and increased bone vascularisation. However, in contrast to NF1 patients, spontaneous fractures do not occur in Nf1Prx1 mice probably due to the relatively low mechanical load. We studied bone healing in a cortical bone injury model in Nf1Prx1 mice as a model for NF1-associated bone disease. Taking advantage of this experimental model we explore effects of systemically applied lovastatin, a cholesterol-lowering drug, on the Nf1 deficient bone repair. Cortical injury was induced bilaterally in the tuberositas tibiae in Nf1Prx1 mutant mice and littermate controls according to a method described previously. Paraffin as well as methacrylate sections were analysed from each animal. We divided 24 sex-matched mutant mice into a lovastatin-treated and an untreated group. The lovastatin-treated mice received 0.15 mg activated lovastatin by daily gavage. The bone repair process was analysed at three consecutive time points post injury, using histological methods, micro computed tomography measurements and in situ hybridisation. At each experimental time point, three lovastatin-treated mutant mice, three untreated mutant mice and three untreated control mice were analysed. The animal group humanely killed on day 14 post injury was expanded to six treated and six untreated mutant mice as well as six control mice. Bone injury repair is a complex process, which requires the concerted effort of numerous cell types. It is initiated by an inflammatory response, which stimulates fibroblasts from the surrounding connective tissue to proliferate and fill in the injury site with a provisional extracellular matrix. In parallel, mesenchymal progenitor cells from the periost are recruited into the injury site to become osteoblasts. In Nf1Prx1 mice bone repair is delayed and characterised by the excessive formation and the persistence of fibro-cartilaginous tissue and impaired extracellular matrix mineralisation. Correspondingly, expression of Runx2 is downregulated. High-dose systemic lovastatin treatment restores Runx2 expression and accelerates new bone formation, thus improving cortical bone repair in Nf1Prx1 tibia. The bone anabolic effects correlate with a reduction of the mitogen activated protein kinase pathway hyper-activation in Nf1-deficient cells. Our data suggest the potential usefulness of lovastatin, a drug approved by the US Food and Drug Administration in 1987 for the treatment of hypercholesteraemia, in the treatment of Nf1-related fracture healing abnormalities. The experimental model presented here constitutes a valuable tool for the pre-clinical stage testing of candidate drugs, targeting Nf1-associated bone dysplasia.
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影响因子：
4.2
作者：
Campbell, TM;Wong, WT;Mackie, EJ
通讯作者：
Mackie, EJ
影响因子：
2.8
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