Short-term intermittent parathyroid hormone (1-34) administration increased angiogenesis and matrix metalloproteinase 9 in femora of mature and middle-aged C57BL/6 mice

Modified Protocol for Establishment of Intracranial Arterial Dolichoectasia Model by Injection of Elastase Into Cerebellomedullary Cistern in Mice

Background and Purpose

This study aimed to construct an animal model of intracranial arterial dolichoectasia (IADE) applying the modified modeling protocol.

Materials and Methods

Twenty five milliunits elastase and inactivated elastase were, respectively, injected into the cerebellomedullary cistern of 60 C57/BL6 mice which were divided into experimental group (EG, n = 30) and control group (CG, n = 30) by using a computer-based random order generator. The modified modeling protocol clarified these aspects including brain three-dimensional parameters of mouse head fixation, angle of head inclination, fixed position of taper ear, needle holding technique, needle entry depth, prevention of liquid drug back flow, and storage conditions of elastase. And it was observed for the following parts such as mortality, inflammatory factors, craniocerebral arteries scanning, vascular tortuosity index, artery diameter, pathology of the cerebrovascular.

Results

Within differently surveyed stage, the total mortality of mice in EG was 20%. ELISA illustrated that the levels of matrix metalloproteinase-9 (MMP-9) and tumor necrosis factor α (TNF-α) in peripheral blood were increased significantly after modeling. Angiography indicated that 100% of IADE in EG were observed and the diameter and tortuosity index of the basilar artery were significantly increased (P < 0.01). EVG histological processing and staining showed the disrupted internal elastic lamina, the atrophied muscle layer, and the hyalinized connective tissue of the basilar artery with the vascular wall tunica media in EG. Micro-computed tomography reported that the craniocerebral arteries of the mice in EG were outstandingly elongated, tortuous, and dilated.

Conclusion

The modified modeling protocol can reduce the mortality, improve the success rate, and provide a stable animal model for IADE.

Systemic Administration of PTH Supports Vascularization in Segmental Bone Defects Filled with Ceramic-Based Bone Graft Substitute

Non-unions continue to present a challenge to trauma surgeons, as current treatment options are limited, duration of treatment is long, and the outcome often unsatisfactory. Additionally, standard treatment with autologous bone grafts is associated with comorbidity at the donor site. Therefore, alternatives to autologous bone grafts and further therapeutic strategies to improve on the outcome and reduce cost for care providers are desirable. In this study in Sprague–Dawley rats we employed a recently established sequential defect model, which provides a platform to test new potential therapeutic strategies on non-unions while gaining mechanistic insight into their actions. The effects of a combinatorial treatment of a bone graft substitute (HACaS+G) implantation and systemic PTH administration was assessed by µ-CT, histological analysis, and bio-mechanical testing and compared to monotreatment and controls. Although neither PTH alone nor the combination of a bone graft substitute and PTH led to the formation of a stable union, our data demonstrate a clear osteoinductive and osteoconductive effect of the bone graft substitute. Additionally, PTH administration was shown to induce vascularization, both as a single adjuvant treatment and in combination with the bone graft substitute. Thus, systemic PTH administration is a potential synergistic co-treatment to bone graft substitutes.