Establishment And Preliminary Analysis Of Skeletal Muscle Specific Knockout FGF9 Mouse Model And Its Role In Skeletal Muscle Injury

Part one Skeletal muscle specific knockout FGF9 mouse model wasestablishedObjective: FGF9 plays an important role in many biological processes,however,there are few studies on the role and mechanism of FGF9 in skeletal muscle.Therefore,we used Cre-Loxp technique to establish the animal model of the skeletal muscle net to knock out FGF9,thus laying a foundation for further study of the role of FGF9 in skeletal muscle and its mechanism.Methods:Used Cre-Loxp technique and finally FGF9^flox/flox/Cre⁺mice were obtained,then the pathological sections were stained with immunofluorescence staining.Results:1.Gene identified FGF9flox/wt/Cre⁺mice;2.Genes identified FGF9^flox/flox/Cre⁺mice;3.Immunofluorescence confirmed that the specific knockout of skeletal muscle was FGF9.Conclusions:The successful establishment of skeletal muscle specific knockout FGF9 mouse model.Part two The preliminary analysis of skeletal muscle specific knockout FGF9 mouse model and the role of FGF9 in skeletal muscle injury were studied.Objective: The damage repair of skeletal muscle mainly relies on the activation,proliferation and differentiation of muscle satellite cells,as well as the involvement of inflammatory macrophages and a large number of cytokines such as FGF9.First preliminary pathological analysis of FGF9^flox/flox/Cre⁺mice,then making the model of skeletal muscle damage,thus further study FGF9 role in skeletal muscle damage and its mechanism.Methods:1.Preliminary analysis of FGF9^flox/flox/Cre⁺pathological features.2.The model of skeletal muscle injury in mice was established by using bupivacaine hydrochloride.3.Muscle strength test.4.HE staining,masson staining and immunofluorescence of frozen sections.5.Quantitative evaluation of histological parameters.Results:1 The FGF9^flox/flox/Cre⁺mouse group had no significant difference in body weight,muscle cell diameter,and area size compared to the FGF9 flox/flox mouse group?P>0.05?,both on routine pathological staining no difference.2 Research on skeletal muscle injury2.1 HE-stainingIn the FGF9^flox/flox/Cre⁺mouse group of injury 3d,5d,7d,compared with the FGF9^flox/flox mouse group,the necrosis was severe and the regeneration ability was weak?P<0.05?.2.2 Anterior tibial muscle strength testFGF9^flox/flox/Cre⁺mice than FGF9^flox/flox mice group in skeletal muscle injury in 3d,5d,7d strength small?P<0.05?,damage to the muscle proximity between 14 d,then skeletal muscle cell regeneration has returned to matureskeletal muscle cell size?P>0.05?.2.3 Skeletal muscle injury fibrosisThe fibrosis area of FGF9^flox/flox/Cre⁺mice in the same period was less than that of FGF9^flox/flox mice?P<0.01?.2.4 Macrophage immunofluorescence after skeletal muscle injuryAt 3d,5d,and 7d of skeletal muscle injury,more CD68-positive cells were observed in the FGF9^flox/flox/Cre⁺mouse group compared to the FGF9^flox/flox mouse group,and CD206-positive cells were less?P<0.05?at The number of positive cells was similar between 14 d and 28d?P>0.05?.Conclusions:1.Skeletal muscle specific knockout FGF9 mouse model were unchanged compared with normal mice.2.FGF9 can play a role of anti-necrosis and regeneration.3.FGF9 can participate in the damage repair of skeletal muscle by reducing CD68 positive m1-type macrophages and increasing CD206 positive m2-type macrophages.4.Knockout of FGF9 can reduce fibrosis.