OSTEOPENIA in cancellous bone of sheep induced by Glucocorticoid alone
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OSTEOPENIA in cancellous bone of sheep induced by Glucocorticoid alone. / Ding, Ming; Cheng, L.; Bollen, Peter; Schwarz, Peter; Overgaard, Søren.
In: Journal of Bone and Joint Surgery: British Volume, Vol. 91-B, No. SUPP III, 449, 2008, p. 63-63.Research output: Contribution to journal › Conference abstract in journal › Research
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TY - ABST
T1 - OSTEOPENIA in cancellous bone of sheep induced by Glucocorticoid alone
AU - Ding, Ming
AU - Cheng, L.
AU - Bollen, Peter
AU - Schwarz, Peter
AU - Overgaard, Søren
N1 - Conference code: 20
PY - 2008
Y1 - 2008
N2 - Introduction: There is a great need for suitable large animal models that closely resemble osteoporosis in humans, and that they have adequate bone size for bone prosthesis and biomaterial research. Previous investigations have shown that osteoporotic sheep model requires glucocorticoid (GC) treatment for a long period of time after ovariectomy (OVX) to induce osteoporosis (1). However, no information in literature is available whether osteoporosis (OP) in sheep can be induced by application of GC alone. This study aimed to investigate effects of GC alone without OVX on three-dimensional (3-D) microarchitectural properties and mechanical properties of sheep cancellous bone after a 7 months steroid treatment; and thus to validate a large animal model for orthopaedic implant/biomaterial research.Materials and Methods:Eighteen female sheep were randomly allocated into 3 groups: group 1 (GC-1) received GC (0.60mg/kg/day methylprednisolone) 5 days weekly for 7 months; group 2 (GC-2) received the same treatment regime for 7 months, and further observed for 3 months without GC; and group 3 served as the control group, and left untreated for 7 months. The sheep were housed outdoors, and received restricted diet, i.e. grass pellets (0.55% calcium and 0.35% phosphorus) and hay.After sacrifice, cancellous bone specimens from 5th lumbar vertebra, distal femur and proximal tibia were micro-CT scanned (vivaCT 40, Scanco Medical AG., Switzerland) to quantify their 3-D microarchitecture(2), and then bone samples were tested compressively (MTS Systems Co., USA) to determine their mechanical properties. At sacrifice, serum samples were collected, and biomarkers for bone formation (Osteocalcin) and resorption (Crosslaps) were determined. The results were analyzed statistically. One-way ANOVA were performed, A p-value <0.05 was considered significant. Results: After 7 months of GC treatment. Cancellous bone volume fraction of the 5th lumbar vertebra in the GC-1 group was reduced by -35%, trabecular thickness by -28%, and changed from typical plate structure to a combination of plate and rod structure with increased connectivity by 202% (Fig 1 & Table 1). Bone strength was reduced by 52% (Table 1). Bone formation marker, serum osteocalcin of GC-1, was reduced by 71% at 7 months, but recovered with an increase of 45% at 10 month in the GC-2 group (Fig 1). Similar trends were also seen in the femur and tibia. At 10 months, the GC-2 group had microarchitectural and mechanical properties similar to the level of the control sheep. Discussion and Conclusion: For the first time we have demonstrated that 7 month high-dose GC on bone density and microarchitecture are comparable with those observed in human after long-term GC treatment. Moreover, we have shown that the bone quality with regard to strength and microarchitecture recovers after 3 months further observation without GC. This suggests that a prolonged administration of GC is needed for long-term observation to keep osteopenic bone. Interestingly, osteocalcin was significantly reduced after 7 months but a rebound phenomenon was observed 3 months after cessation of GC. In conclusion, this study has validated an osteopenia sheep model. Bone quality was significantly reduced following a 7 months GC-treatment and recovered after further 3 month observation without treatment. The model will be useful in pre-clinical studies.
AB - Introduction: There is a great need for suitable large animal models that closely resemble osteoporosis in humans, and that they have adequate bone size for bone prosthesis and biomaterial research. Previous investigations have shown that osteoporotic sheep model requires glucocorticoid (GC) treatment for a long period of time after ovariectomy (OVX) to induce osteoporosis (1). However, no information in literature is available whether osteoporosis (OP) in sheep can be induced by application of GC alone. This study aimed to investigate effects of GC alone without OVX on three-dimensional (3-D) microarchitectural properties and mechanical properties of sheep cancellous bone after a 7 months steroid treatment; and thus to validate a large animal model for orthopaedic implant/biomaterial research.Materials and Methods:Eighteen female sheep were randomly allocated into 3 groups: group 1 (GC-1) received GC (0.60mg/kg/day methylprednisolone) 5 days weekly for 7 months; group 2 (GC-2) received the same treatment regime for 7 months, and further observed for 3 months without GC; and group 3 served as the control group, and left untreated for 7 months. The sheep were housed outdoors, and received restricted diet, i.e. grass pellets (0.55% calcium and 0.35% phosphorus) and hay.After sacrifice, cancellous bone specimens from 5th lumbar vertebra, distal femur and proximal tibia were micro-CT scanned (vivaCT 40, Scanco Medical AG., Switzerland) to quantify their 3-D microarchitecture(2), and then bone samples were tested compressively (MTS Systems Co., USA) to determine their mechanical properties. At sacrifice, serum samples were collected, and biomarkers for bone formation (Osteocalcin) and resorption (Crosslaps) were determined. The results were analyzed statistically. One-way ANOVA were performed, A p-value <0.05 was considered significant. Results: After 7 months of GC treatment. Cancellous bone volume fraction of the 5th lumbar vertebra in the GC-1 group was reduced by -35%, trabecular thickness by -28%, and changed from typical plate structure to a combination of plate and rod structure with increased connectivity by 202% (Fig 1 & Table 1). Bone strength was reduced by 52% (Table 1). Bone formation marker, serum osteocalcin of GC-1, was reduced by 71% at 7 months, but recovered with an increase of 45% at 10 month in the GC-2 group (Fig 1). Similar trends were also seen in the femur and tibia. At 10 months, the GC-2 group had microarchitectural and mechanical properties similar to the level of the control sheep. Discussion and Conclusion: For the first time we have demonstrated that 7 month high-dose GC on bone density and microarchitecture are comparable with those observed in human after long-term GC treatment. Moreover, we have shown that the bone quality with regard to strength and microarchitecture recovers after 3 months further observation without GC. This suggests that a prolonged administration of GC is needed for long-term observation to keep osteopenic bone. Interestingly, osteocalcin was significantly reduced after 7 months but a rebound phenomenon was observed 3 months after cessation of GC. In conclusion, this study has validated an osteopenia sheep model. Bone quality was significantly reduced following a 7 months GC-treatment and recovered after further 3 month observation without treatment. The model will be useful in pre-clinical studies.
M3 - Conference abstract in journal
VL - 91-B
SP - 63
EP - 63
JO - Journal of Bone and Joint Surgery: British Volume
JF - Journal of Bone and Joint Surgery: British Volume
SN - 2049-4394
IS - SUPP III, 449
Y2 - 26 September 2012 through 28 September 2012
ER -
ID: 252048927