Study on the characteristics of bone remodeling in ovariectomized mice

doi:10.11958/20250846

Abstract

Abstract:

Objective To explore the effect of estrogen deficiency on bone remodeling characteristics in an ovariectomized mouse model. Methods Ten 12-week-old female C57BL/6J mice were randomly divided into the sham operation group and the ovariectomy (OVX) group, with 5 mice in each group. The uteri of mice were isolated at 16 weeks postoperatively. The morphology was observed, and uterine weights were counted. CT scans were performed to analyze the distal femur of the mice, and anti-tartrate acid phosphatase (TRAP) staining was performed to assess the number of osteoclasts in paraffin sections of femoral tissue. Bone marrow-derived mesenchymal stem cells (BM-MSCs) and bone marrow-derived macrophages (BMMs) were sorted from femoral bone marrow of mice using CD11b magnetic beads. Alkaline phosphatase (ALP) staining was performed to assess the osteogenic differentiation potential of BM-MSCs. Reverse transcription-quantitative PCR (RT-qPCR) was performed to detect the expression levels of genes related to osteogenic differentiation of BM-MSCs (Runx2, Sp7, and Spp1) and osteoclast differentiation of BMMs (Ctsk, Acp5, and Cd40). Results Compared with the sham group, the uterus of the OVX group showed significant atrophy and weight loss, and bone mineral density (BMD), bone volume fraction (BV/TV), bone surface area tissue volume ratio (BS/TV), number of trabeculae (Tb.N), trabecular thickness (Tb.Th), cortical bone mineral density (Ct.BMD) and cortical bone thickness (Ct.Th) were significantly reduced, and bone trabecular separation (Tb.Sp) was significantly increased (P<0.01). The mRNA expression levels of Runx2, Sp7 and Spp1 were reduced in BM-MSCs of the OVX group compared with the sham group (P<0.01). The osteogenic differentiation was also diminished after induction. The mRNA expression levels of Ctsk, Acp5 and Cd40 were elevated in the BMMs of the OVX group, and the number of osteoclasts in bone marrow of the distal femur was greater in the OVX group than that in the sham group (P<0.01). Conclusion OVX-induced estrogen deficiency can enhance osteoclast differentiation and attenuate osteogenic differentiation capacity, ultimately causing dysregulation of bone homeostasis and resulting in osteoporosis.

Key words: ovariectomy, estrogens, macrophages, mesenchymal stem cells, bone remodeling

CLC Number:

R332

Figures/Tables 9

References 14

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基因名称	引物序列（5'→3'）	产物大小/bp
Ctsk	上游：GAGGGCCAACTCAAGAAGAA 下游：TTGGAAGGCAGTGGTCATATAG	117
Acp5	上游：CCTGAGATTTGTGGCTGTGG 下游：TCTTGTCGCTGGCATCGTG	179
Cd40	上游：GTCGGCTTCTTCTCCAATCA 下游：CTGACTCGTTCCTTTCTGTAGG	102
Runx2	上游：CTCTGCACCAAGTCCTTTTAATC 下游：AGGAGGGGTAAGACTGGTCATAG	104
Sp7	上游：CTGAGAGAGGAGCAGATCCC 下游：GTGAGCTTCTTCCTGGGTAGG	120
Spp1	上游：ATCTCACCATTCGGATGAGTCT 下游：TGTAGGGACGATTGGAGTGAAA	79
GAPDH	上游：ATTGTCAGCAATGCATCCTG 下游：ATGGACTGTGGTCATGAGCC	102

基因名称	引物序列（5'→3'）	产物大小/bp
Ctsk	上游：GAGGGCCAACTCAAGAAGAA 下游：TTGGAAGGCAGTGGTCATATAG	117
Acp5	上游：CCTGAGATTTGTGGCTGTGG 下游：TCTTGTCGCTGGCATCGTG	179
Cd40	上游：GTCGGCTTCTTCTCCAATCA 下游：CTGACTCGTTCCTTTCTGTAGG	102
Runx2	上游：CTCTGCACCAAGTCCTTTTAATC 下游：AGGAGGGGTAAGACTGGTCATAG	104
Sp7	上游：CTGAGAGAGGAGCAGATCCC 下游：GTGAGCTTCTTCCTGGGTAGG	120
Spp1	上游：ATCTCACCATTCGGATGAGTCT 下游：TGTAGGGACGATTGGAGTGAAA	79
GAPDH	上游：ATTGTCAGCAATGCATCCTG 下游：ATGGACTGTGGTCATGAGCC	102

组别	BMD/（mg/cm³）	BV/TV/%	BS/TV/（1/mm）
Sham组	181.00±6.38	30.95±1.72	43.12±3.62
OVX组	132.90±7.49	15.11±2.89	27.77±2.08
t	10.910^＊＊	10.520^＊＊	8.220^＊＊
组别	Tb.N/（1/cm）	Tb.Th/mm	Tb.Sp/cm
Sham组	10.72±0.54	0.053±0.003	0.044±0.004
OVX组	8.24±0.44	0.044±0.002	0.076±0.006
t	7.962^＊＊	6.796^＊＊	9.868^＊＊

组别	BMD/（mg/cm³）	BV/TV/%	BS/TV/（1/mm）
Sham组	181.00±6.38	30.95±1.72	43.12±3.62
OVX组	132.90±7.49	15.11±2.89	27.77±2.08
t	10.910^＊＊	10.520^＊＊	8.220^＊＊
组别	Tb.N/（1/cm）	Tb.Th/mm	Tb.Sp/cm
Sham组	10.72±0.54	0.053±0.003	0.044±0.004
OVX组	8.24±0.44	0.044±0.002	0.076±0.006
t	7.962^＊＊	6.796^＊＊	9.868^＊＊

组别	Ct.BMD/（mg/cm³）	Ct.Th/cm
Sham组	886.80±22.41	0.050±0.001
OVX组	815.10±16.01	0.042±0.003
t	5.816^＊＊	6.558^＊＊