Zoledronate loaded polylactic acid/polycaprolactone/hydroxyapatite scaffold accelerates regeneration and led to enhance structural performance and functional ability of the radial bone defect in rat

Abstract.

Background

One of the most common concerns in the regeneration of massive bone defects necessitating surgery and bone grafts is the application of tissue engineering using drug delivery. Zoledronate is a well-known effective drug for the healing bone fractures in osteoporotic patients.

Aims

An attempt was made to design a more efficient bone scaffold with polycaprolactone, polylactic acid, and hydroxyapatite.

Methods

The scaffold was fabricated by freeze-drying and indirect 3D printing approaches. X-ray diffraction, Fourier transform infrared spectroscopy, rheometry, scanning electron microscopy, and neutral red tests were performed to characterize the scaffold. qRT-PCR was also done to define the osteoinductivity and angiogenic induction capacity of this scaffold. Forty rats were selected and randomly divided into four groups: the control group, which received no treatment, the autograft group, scaffold group, and Zol-loaded scaffold group (n=10 in each group). The injured area was studied by radiology, biomechanical analysis, histopathology, histomorphometry, immunohistochemistry, and CT scan analyses.

Results

The qRT-PCR results demonstrated significantly higher expression levels of OPN, OCN, and CD31 markers in the scaffold group when compared to the control group (P<0.05). Histopathologically, the newly formed bone tissue was significantly detected in the Zol-loaded scaffold and autograft groups in comparison with the non-treated group (P<0.001). The immunohistochemistry (OC marker), biomechanical, and histomorphometric results indicated a significant improvement in the regeneration of the injured area in the groups treated with autologous bone and Zol-loaded scaffold compared to the non-treated group (P<0.05). Conclusion: The Zol-loaded scaffold accelerated bone regeneration, and led to enhanced structural performance and functional ability of the injured radial bone in rats.

A rare case report of extensive mandibular osteoma corrected by unilateral mandibulectomy: cytological, radiological, and pathological investigation

Background: Osteoma is a benign bone tumor that rarely affects animals. The most common bones involved with this tumor included the mandible, maxillofacial bones, and nasal sinuses. Definitive diagnosis is based on pathology findings which allow for differentiation with other bone lesions. Case Description: The patient, a five-year-old intact male Mongrel dog presented with a huge mandibular mass that involved both the right and left mandible, and led to dental occlusion. The radiography was performed and depicted the intense mass with a well-demarcated edge, a short transitional zone between normal and abnormal bone, and a smooth rounded radiopaque appearance. The investigation according to the fine needle aspiration showed the presence of oval to spindle shape cells with poorly malignancy criteria, fatty cells, reactive osteoblasts and osteoclasts based on a population of spindle-shaped cells, and low numbers of degenerated neutrophils, bacteria, and few macrophages. Then, the radiographic assessments and cytology findings demonstrated the osteoma and referred for surgical intervention. A unilateral mandibulectomy was performed, and the lesion was send to the histopathology laboratory. The histopathology evaluation showed osteocyte proliferation without malignancy features. The osteoblast cells also showed no atypical proliferation that endorses the osteoma tumor. Conclusion: Although, mandibular and maxillofacial bone resection in small animals have different tolerations, this patient became a candidate for surgery for future better nutrition and prevention of facial deformity and dental malocclusion. Follow-up after osteoma is one of the most necessary post-operation treatments to check the regeneration of the mass. There are considerable data in this report that should regard this tumor as a possible differential diagnosis for mandibular tumors.

Role of bone 1stem cell-seeded 3D polylactic acid/polycaprolactone/hydroxyapatite scaffold on a critical-sized radial bone defect in rat

Osteoconductive biomaterials were used to find the most reliable materials in bone healing. Our focus was on the bone healing capacity of the stem cell-loaded and unloaded PLA/PCL/HA scaffolds. The 3D scaffold of PLA/PCL/HA was characterized by scanning electron microscopy (SEM), rheology, X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy. Bone marrow stem cells (BMSCs) have multipotential differentiation into osteoblasts. Forty Wistar male rats were used to organize four experimental groups: control, autograft, scaffold, and BMSCs-loaded scaffold groups. qRT-PCR showed that the BMSCs-loaded scaffold had a higher expression level of CD31 and osteogenic markers compared with the control group (P < 0.05). Radiology and computed tomography (CT) scan evaluations showed significant improvement in the BMSCs-loaded scaffold compared with the control group (P < 0.001). Biomechanical estimation demonstrated significantly higher stress (P < 0.01), stiffness (P < 0.001), and ultimate load (P < 0.01) in the autograft and BMSCs-loaded scaffold groups compared with the untreated group and higher strain was seen in the control group than the other groups (P < 0.01). Histomorphometric and immunohistochemical (IHC) investigations showed significantly improved regeneration scores in the autograft and BMSCs-loaded scaffold groups compared with the control group (P < 0.05). Also, there was a significant difference between the scaffold and control groups in all tests (P < 0.05). The results depicted that our novel approach will allow to develop PLA/PCL/HA 3D scaffold in bone healing via BMSC loading.

Effectiveness of a biodegradable 3D polylactic acid/poly(ɛ-caprolactone)/hydroxyapatite scaffold loaded by differentiated osteogenic cells in a critical-sized radius bone defect in rat

The effects of a scaffold made of polylactic acid, poly (ɛ-caprolactone) and hydroxyapatite by indirect 3D printing method with and without differentiated bone cells was tested on the regeneration of a critical radial bone defect in rat. The scaffold characterization and mechanical performance were determined by the rheology, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectrometry. The defects were created in forty Wistar rats which were randomly divided into the untreated, autograft, scaffold cell-free, and differentiated bone cell-seeded scaffold groups (n = 10 in each group). The expression level of angiogenic and osteogenic markers, analyzed by quantitative real time-polymerase chain reaction (in vitro), significantly improved (p < 0.05) in the scaffold group compared to the untreated one. Radiology and computed tomography scan demonstrated a significant improvement in the cell-seeded scaffold group compared to the untreated one (p < 0.001). Biomechanical, histopathological, histomorphometric, and immunohistochemical investigations showed significantly better regeneration scores in the cell-seeded scaffold and autograft groups compared to the untreated group (p < 0.05). The cell-seeded scaffold and autograft groups did show comparable results on the 80^th day post-treatment (p > 0.05), however, most results in the scaffold group were significantly higher than the untreated group (p < 0.05). Differentiated bone cells can enhance bone regeneration potential of the scaffold.

Effects of bisphosphonates on osteoporosis: Focus on zoledronate

Osteoporosis is a bone disease that mainly affects older people and postmenopausal women. Lack of proper treatment for this disease gives rise to many problems in patients and occasionally leads to death. Many drugs have been utilized to treat osteoporosis but the most effective one is the bisphosphonates (BPs) family. This family has several positive effects on bone tissue, including promoting bone healing, enhancing bone mineral density, reducing bone resorption, preventing pathologic fractures, suppressing bone turnover, and modulating bone remodeling. On the other hand, there have also been inconclusive reports that BPs might have a desirable or even adverse impact on osteoporotic patients. Therefore, we set out to examine the positive and negative effects of this family, with a focus on the most potent one that is zoledronate (Zol), in clinical usage. Zoledronate is an amino-BPs and nitrogen-containing drug which is the most powerful BPs on osteoporosis treatment or prevention. Many studies showed its effectiveness in the treatment of osteoporosis and bone healing. As Zol enjoys a considerable potential in treating and preventing osteoporosis, it can be used as one of the effective treatments in this field.

Effectiveness of mesenchymal stem cell-seeded onto the 3D polylactic acid/polycaprolactone/hydroxyapatite scaffold on the radius bone defect in rat

PURPOSE

The importance of regeneration in large bone defects forces the orthopedic surgeons to search for a proper methodology. The present experiment evaluated the capability of polylactic acid/polycaprolactone/hydroxyapatite (PLA/PCL/HA) scaffold loaded with and without mesenchymal stem cells (MSCs) on bone regeneration.

METHODS

Fourier transform infrared spectrometry, X-ray diffraction, scanning electron microscopy, and rheology methodologies were used to characterize the scaffold. Forty Wistar rats were randomly divided into the four groups including the untreated defects as the control group and three other groups in which the bone defects were treated with autologous bones (autograft group), the PLA/PCL/HA scaffolds (PLA/PCL/HA group), and the MSCs-seeded scaffolds (MSCs-seeded PLA/PCL/HA group).

RESULTS

Based on the qRT-PCR results, significantly higher expression levels of osteocalcin, osteopontin, and CD31 were seen in the cell-seeded scaffold group compared to the control group (P < 0.05). The CT scanning and radiographic images depicted significantly more newly formed bonny tissue in the MSCs-loaded scaffold and autograft groups than the untreated group (P < 0.001). The immunohistochemistry, biomechanical, histopathologic, and histomorphometric evaluations demonstrated significantly improved regeneration in the autograft and MSCs-loaded scaffold groups compared to the non-treated group (P < 0.05). There were significant differences between the scaffold and untreated groups in all in vivo evaluations (P < 0.05).

CONCLUSION

The MSCs enhanced bone healing potential of the PLA/PCL/HA scaffold and the MSCs-seeded scaffold was comparable to the autograft as the golden treatment regimen (P > 0.05).