Objective: To investigate changes in lactate and histone lactylation during senescence of mouse bone marrow mesenchymal stem cells (BMSCs), to clarify the effects of regulating lactate metabolism on the osteogenic differentiation of senescent BMSCs, and to provide theoretical evidence and an experimental basis for metabolic regulatory interventions in aging-related osteoporosis and impaired bone repair. Methods: Approval was obtained from the Institutional Laboratory Animal Ethics Committee. BMSCs were isolated using the whole bone marrow adherence method and surface markers (CD29, CD90, CD11b and CD45) and identified by flow cytometry. A cellular model of BMSCs senescence was established using different concentrations of etoposide (0, 5, 10, 15, and 20 μmol/L). The gene and protein expression levels of senescence-related markers, namely, p53, p21, and p16, were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot analysis, and the optimal induction concentration was determined using CCK-8 and SA-β-gal assays. BMSCs were divided into a control group and an etoposide-induced senescence group to examine lactate production and the expression of histone lactylation-related enzymes, including Ldha, Ep300, and Sirt2. Western blot analysis was used to analyze pan-lysine lactylation（Pan-Kla） and histone H3 lysine 18 lactylation （H3K18la). During the lactate production inhibition experiments, BMSCs were divided into three groups: control, senescence group (treated with 10 μmol/L etoposide), and senescence+ GNE-140 group (treated with 10 μmol/L etoposide and 1 μmol/L GNE-140). qRT-PCR, Western blot, and SA-β-gal staining were performed to assess the effects of lactate production inhibition on cellular senescence phenotypes. During osteogenic differentiation, BMSCs were assigned to a control group, senescence group (treated with 10 μmol/L etoposide), senescence+ 5 mmol/L sodium lactate group, and senescence+ 10 mmol/L sodium lactate group. The levels of Pan-Kla and H3K18la were detected by Western blot. The mRNA expressions of runt-related transcription factor 2 (Runx2), transcription factor Sp7 (Sp7) and alkaline phosphatase (Alpl) were detected by qRT-PCR. The protein expressions of collagen type I (COL1), RUNX2, osterix (OSX) and osteocalcin (OCN) were detected by Western blot, and mineralized nodule formation was observed by Alizarin Red S staining. Results: Flow cytometry analysis indicated that the isolated BMSCs highly expressed CD29 (97.3%) and CD90 (95.7%). Etoposide induced BMSC senescence by activating the p53-p21 signaling pathway, with an optimal concentration of 10 μmol/L. Compared with the control group, BMSCs exhibited decreased lactate production, reduced mRNA expression of Ldha and Ep300 (P<0.001), upregulated Sirt2 expression (P<0.01), and diminished levels of Pan-Kla and H3K18la modification (P<0.001). Further inhibition of lactate production with GNE 140 further increased the expression levels of p53 and p21 and the percentage of SA β gal positive cells (P<0.01). In osteogenic differentiation experiments, the expression levels of Runx2, Sp7, Alpl mRNA and COL1, RUNX2, OSX, OCN proteins, as well as the mineralized nodule formation ability of senescent BMSCs, were decreased (P<0.05); exogenous supplementation with 5 mmol/L and 10 mmol/L sodium lactate can increase the levels of panolactic lactation and histone lactation, and improved the osteogenic differentiation capacity and mineralized nodule formation of senescent BMSCs. Conclusion BMSC senescence is associated with reduced lactate production and decreased histone lactylation levels. Exogenous supplementation with sodium lactate partially rescues osteogenic differentiation impairment in senescent BMSCs.