Nordsletten, J. energy, deflection, callus diameter, DXA measurements (n = 64), histomorphometrically osteoid/bone ratio, or callus area (n = 20). Conclusion This study demonstrates no negative effect of immediate or delayed short-term administration of Linagliptin (BI-1356) parecoxib on diaphyseal fracture healing in rats. Cite this article: G. A. Hjorthaug, E. S?reide, L. Nordsletten, J. E. Madsen, F. P. Reinholt, S. Niratisairak, S. Dimmen. Short-term perioperative parecoxib is not detrimental to shaft fracture healing in a rat model. 2019;8:472C480. DOI: 10.1302/2046-3758.810.BJR-2018-0341.R1. at four weeks of healing. Orientation is proximal (P) to distal (D). a) Fractured (F) and non-fractured (NF) tibia from a specimen (parecoxib immediate (Pi) group) prepared for biomechanical tests. b) Segment of middle tibia containing callus in a specimen (control group) fixed for histological analysis. Histological evaluation Tissues of animals allocated to histological evaluation were fixed by vascular perfusion of 0.1 M phosphate-buffered 2% paraformaldehyde during deep anaesthesia. Following removal of the nail, fibula, and soft tissues, a 15 mm tibial shaft segment containing the fracture with callus was harvested using Linagliptin (BI-1356) an oscillating saw (Fig. 2b). These segments were fixed overnight in the same fixative as mentioned above, dehydrated in series of ethanol, incubated, and embedded in plastic (K-plast; DiaTec Systems for Laboratory, Hallstadt, Germany), following a standard protocol. The undecalcified specimens were cut from anterior to posterior (thickness 5 m). The central section containing the thickest callus was chosen as the region of interest (ROI). Histomorphometry MassonCGoldners trichrome-stained sections were evaluated by light microscopy. Digital images were analyzed using AnalySIS V (Olympus Soft Imaging Solutions, Mnster, Germany). The ROI was defined at 1.25 magnification by outlining the perimeter of the callus, including any cortical fracture surface, but excluding original cortical or trabecular bone, periosteum, and bone marrow. This ROI was Linagliptin (BI-1356) defined as total callus area. A virtual grid of lines (random angles, space 100 m) was superimposed onto sections at 10 magnification. Presence of osteoid surfaces or mineralized bone surfaces was noted. The osteoid surface per bone surface (OS/BS; %) were calculated as an indirect measure of bone formation (Fig. 3a). Presence of cartilage within the callus ROI was registered in each specimen (Fig. 3b). The nomenclature used is in accordance with the recommendations of the American Society for Bone and Mineral Research (ASBMR).19 Open in a separate window Fig. 3 High-power magnification light microscopy of tibial fracture calluses. MassonCGoldner trichrome staining of mineralized tissue provides good differentiation between osteoid (O, purple) and mineralized bone matrix (MdB, green). Non-mineralized bone marrow (BMa, red) is distributed between the mineralized bone trabeculae. a) Woven bone formation (control group) with mainly osteoid trabecular surfaces (OS) and a few bone surfaces (BS). b) An immature region within the callus-containing cartilage (Cg) and partly mineralized matrix ITGA1 with ongoing endochondral ossification. Scale bars = 200 m. Bone mineral measurement and radiological evaluation Bone mineral density (BMD) and bone mineral content (BMC) were measured on the fracture site in all animals using DXA (Lunar PIXImus with software v. 2.10; Lunar, Madison, Wisconsin) immediately after surgery, and again at two and four weeks. The ROI (14 14 pixels) was aligned on the fracture and included the anterior cortical bone, the callus, and the nail. The BMD and BMC ideals were corrected for an individually measured value for the toenail before final analysis. Radiographs were examined for fracture pattern and potential complications (Fig. 4). Open in a separate Linagliptin (BI-1356) windowpane Fig. 4 Representative lateral radiograph at baseline showing a short oblique tibial fracture (large arrows) fixed with an intramedullary toenail Linagliptin (BI-1356) and concomitant fibular fracture (small arrow). Specimen from your control group. Statistical analysis An power calculation for the sample size was not performed, but the quantity of animals was estimated based on earlier studies.7,8 The main outcome was the ultimate bending moment percentage between fractured and non-fractured tibia. Other outcomes were ratios of bending tightness, energy absorption, deflection, callus AP and ML diameter, and time-dependent difference in BMD and BMC. Two self-employed observers (GAH and SN for biomechanical variables; GAH and Sera for DXA variables) analyzed these outcomes, and the mean ideals were determined and utilized for the statistical analyses. Normality of the distribution was evaluated using histograms with.