Karaman İbrahim, Günay Ali Eray, Yerer Mükerrem Betül, Demirpolat Eren, Doğan Serap, Hanım Yay Arzu, Kafadar İbrahim Halil
Department of Orthopedics and Traumatology, Erciyes University, School of Medicine, Kayseri, Turkey.
Clinic of Orthopedics and Traumatology, Kayseri City Hospital, Kayseri, Turkey.
Acta Orthop Traumatol Turc. 2020 May;54(3):320-329. doi: 10.5152/j.aott.2020.03.529.
This study aimed to determine the effects of a natural diterpenoid, kirenol, on fracture healing in vivo in an experimental rat model of femur fracture and investigate its potential mechanism of action via the Wnt/β-catenin pathway.
In this study, 64 male Wistar albino rats aged 5-7 weeks and weighing 261-348 g were randomly divided into 8 groups from A to L, with eight rats in each group. Standardized fractures were created in the right femurs of the rats and then fixed with an intramedullary Kirschner wire. Four experimental groups were administered 2 mg/kg/day kirenol (Groups C and G) and 4 mg/kg/day (Groups D and H) kirenol by oral gavage.Thereafter, the animals were sacrificed at two time points as follows: on the 10th day (Groups B, C and D) and on the 21st day (Groups F, G and H) after the surgery; fracture healing in each group was assessed radiologically and histopathologically. The Radiographic Union scale of tibia fracture scoring system was used in the radiological examination; callus volume and density were measured using computed tomography. In the histopathologic examination, the scoring system described by Huo et al. was used. Additionally, the mechanism of action was evaluated based on the analyses of protein expression of Wnt3a, LRP5, TCF-LEF1, β-catenin, and Runx-2 proteins using western blot analysis.
Among the animals sacrificed on the 10th day after the surgery, the highest histopathological and radiological scores were observed in Group D (p<0.05). Furthermore, the callus density (p<0.05) was highest in Group D. Among the animals sacrificed on the 21st day, the highest histopathological and radiological scores were found in Group H, although the differences among the groups were not significant (p>0.05). The callus volume and density were the highest in Groups G and H, respectively, although the differences among groups were not significant.
Kirenol may improve fracture healing in a dose-dependent manner with the early activation of the Wnt/β-catenin pathway and the activation of the Runx-2 pathway.
本研究旨在确定一种天然二萜类化合物——吉壬醇对实验性大鼠股骨骨折模型体内骨折愈合的影响，并通过Wnt/β-连环蛋白途径研究其潜在作用机制。
本研究中，将64只5-7周龄、体重261-348 g的雄性Wistar白化大鼠随机分为A至L 8组，每组8只。在大鼠右侧股骨制造标准化骨折，然后用髓内克氏针固定。四个实验组通过灌胃给予2 mg/kg/天的吉壬醇（C组和G组）和4 mg/kg/天的吉壬醇（D组和H组）。此后，在以下两个时间点处死动物：手术后第10天（B组、C组和D组）和第21天（F组、G组和H组）；对每组骨折愈合情况进行放射学和组织病理学评估。放射学检查采用胫骨骨折评分系统的影像学愈合标准；使用计算机断层扫描测量骨痂体积和密度。在组织病理学检查中，采用Huo等人描述的评分系统。此外，通过蛋白质印迹分析Wnt3a、LRP5、TCF-LEF1、β-连环蛋白和Runx-2蛋白的表达，评估其作用机制。
在手术后第10天处死的动物中，D组的组织病理学和放射学评分最高（p<0.05）。此外，D组的骨痂密度最高（p<0.05）。在第21天处死的动物中，H组的组织病理学和放射学评分最高，尽管各组之间差异不显著（p>0.05）。G组和H组的骨痂体积和密度分别最高，尽管各组之间差异不显著。
吉壬醇可能通过早期激活Wnt/β-连环蛋白途径和Runx-2途径以剂量依赖的方式促进骨折愈合。
