Due to its huge socio-economic impact a better understating of osteoporotic fracture healing is crucial.
Thirty-one female merino land sheep were randomly divided into four groups. (i) Untreated control-group (C, n=8); (ii) bilateral ovariectomy (OVX, n=7); (iii) OVX and calcium-deficient diet (OVXD, n=8); and (iv) OVXD and additional biweekly corticosteroid injections (OVXDS, n=8). Drill-hole defects (7.5 mm in diameter) were created in the iliac crest. Healing time points were 5 months (M) and 8 M post fracture. Bone healing was histomorphometrically assessed using Movat Pentachrom staining. Cellular changes were detected using TRAP and ALP staining, immunhistochemistry of Type I Collagen (Col I) was performed. Image J was used for image analysis and SPSS software was used to explore statically significant results.
Histomorphometry showed higher total ossified tissue (TOT) and lower total cartilage tissue (TCT) in control group from 5 M to 8 M marking the healing process. In contrast, OVXDS group showed the highest TCT and the lowest TOT at 8 M. Osteoid formation was lower after 8 M than 5 M in control and OVX group, in OVXD and OVXDS group osteoid was higher. The total number of osteoclasts was lower after 8 M than after 5 M in each group. Ratio of osteoclast resorption pits to bone surface was significant lower in control and OVX group throughout the time points compared to OVXD and OVXDS. ALP positive area was lower after 8 M than 5 M in all experimental groups. Interestingly OVXDS group showed significantly higher levels of ALP than all other groups at both time points. Col I signal intensity and area was higher in C and surprisingly in OVXDS group after 8 M compared to 5 M, OVX and OVXD showed lower values after 8 M compared to 5 M.
Currently Col X, RANKL and ASMA IHC are being explored for further cellular discrepancies in osteoporotic fractures.
14 May 2016 - 17 May 2016