Effect Of Osteoblast-specific Knockout Of Wnt5a On The Fracture Healing In Ovariectomized Mice Model

Objectives This experiment explored the effect of osteoblast-specific Wnt5 a knockout on fracture healing in female or transgenic mice with normal or bilateral ovarian removal.Methods 8-week-old Ocn-Cre⁺/Wnt5a^fl/flfemale mice and the littermates Ocn-Cre^-/Wnt5a^fl/flmice produced in the same batch were used as parallel controls.The two groups of genotype mice were divided into 2 groups,4 groups in total and 5 mice in each group.They are: normal estrogen Wnt5 a gene knockout group(NE OcnCre⁺/Wnt5a^fl/fl),normal estrogen wild group(NE OcnCre^-/Wnt5a^fl/fl),ovariectomy?Ovariectomized,OVX?Wnt5a gene knockout group(OVX OcnCre⁺/Wnt5a^fl/fl),wild ovariectomy group(OVX OcnCre^-/Wnt5a^fl/fl).The ovariectomized group underwent ovariectomy at the age of 8 weeks,and the remaining two groups were normally fed.All mice were fractured and modeled at the age of 16 weeks and were sacrificed 3 weeks after fracture modeling.Collect animal specimens and carry out related tests,including: X-ray,MicroCT test and histomorphology test.Collect data for statistical analysis.Results The results of X-ray showed that 3 weeks after the fracture,there was obvious bone callus formation in each group,and a large bone callus formed in the fracture site of the OVX OcnCre^-/Wnt5a^fl/flgroup.The measurement results of the callus area show that the area of the callus of the OVX OcnCre^-/Wnt5a^fl/flgroup is significantly higher than that of the NE OcnCre⁺/Wnt5a^fl/flgroup,NE OcnCre^-/Wnt5a^fl/flgroup and OVX OcnCre⁺/Wnt5a^fl/flgroup?P<0.05?.MicroCT results show that the reconstruction map clearly shows that the bone callus of the NE OcnCre⁺/Wnt5a^fl/flgroup is denser than the other three groups,followed by the NE OcnCre^-/Wnt5a^fl/flgroup,and the OVX OcnCre⁺/Wnt5a^fl/flgroup is the most sparse.The results of morphological parameters show that the NE OcnCre⁺/Wnt5a^fl/flgroup compared with the other three groups of bone callus bone density?BMD?,bone volume fraction?BV/TV?,trabecular bone link density?Conn.d?,trabecular bone The number?Tb.N?increased significantly?P<0.05?,and the trabecular bone separation?Tb.sp?decreased significantly?P<0.05?.Compared with NE OcnCre^-/Wnt5a^fl/flgroup,OVX OcnCre⁺/Wnt5a^fl/flgroup had significantly lower bone volume fraction?BV/TV?and trabecular bone number?Th.N??P<0.05?.HE staining results show that trabecular in the normal group(NE OcnCre^-/Wnt5a^fl/fland NE OcnCre⁺/Wnt5a^fl/fl)are more in the number and more continuous than that of the OVX group(OVX OcnCre^-/Wnt5a^fl/fland OVX OcnCre⁺/Wnt5a^fl/fl).It can be clearly seen that the trabecular bones in the OVX OcnCre⁺/Wnt5a^fl/flgroup are the most sparse and have the worst continuity.Conclusions 1 Among the non-knockout mice,the fracture healing process of bilateral ovariectomized mice was significantly delayed compared to normal mice.2 In mice without ovariectomy,conditional knockout of Wnt5 a in osteoblasts can promote fracture healing.Wnt5 a knockout in the bilateral ovariectomy groups had no significant effect on fracture healing.Figure9;Table7;Reference 71...