Objective To explore the role of secreted phosphoprotein 1(SPP1)and myeloid differentiation primary response 88(MYD88)in morphine-induced cardiomyocyte apoptosis.Methods A morphine addiction model was established in Sprague-Dawley(SD)rats.Twelve SD rats were randomly assigned to the normal saline(NS)group or the morphine-dependent(DAM)group.Histopathological analysis was employed to observe and compare myocardial tissue morphology between the two groups.Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL)staining was performed to assess the number of apoptotic cells in each group.The expression levels of SPP1 and MYD88 were evaluated using immunohistochemistry.Quantitative real-time poly merase chain reaction(RT-qPCR)and Western blot were used to detect the mRNA and protein expression of SPP1,MYD88,Bax,Bcl2,Caspase-3,and Caspase-9.Simultaneously,Western blot analysis was used to detected the expression of Cleaved Caspase-3 and Cleaved Caspase-9 proteins.In vitro,SPP1 expression was knocked down in primary neonatal rat cardiomyocytes(NRCMs),and cells were divided into three groups:control(CON),morphine treated(DA),and shSPP1#3+DA.Cell viability was assessed using the CCK-8 assay,and apoptosis rates were determined by flow cytometry.Results HE and TUNEL staining of myocardial tissues from morphine-addicted SD rats revealed that,compared with the NS group,myofibrils in the DAM group exhibited partial disruption and a significant increase in apoptotic cells(P<0.05).Western blot and RT-qPCR analyses demonstrated that,relative to the NS group,the mRNA and protein levels of SPP1,MYD88,Bax,Caspase-3,and Caspase-9 were significantly upregulated in the DAM group(P<0.05),whereas Bcl2 expression was significantly downregulated at both mRNA and protein levels(P<0.05),and the protein expression levels of Cleaved Caspase-3 and Cleaved Caspase-9 were also increased.with all differences being statistically significant.In NRCMs following morphine intervention,cell viability in the DA group was markedly reduced compared to the CON group(P<0.05),accompanied by a signifi-cant increase in apoptosis rate(P<0.05).Consistently,Western blot and RT-qPCR results showed elevated mRNA and protein expression of SPP1,MYD88,Bax,Caspase-3,and Caspase-9 in the DA group(P<0.05),along with decreased Bcl2 expression(P<0.05).The protein expression levels of Cleaved Caspase-3 and Cleaved Caspase-9 were elevated simultaneously.In contrast,the shSPP1#3+DA group exhibited opposing trends compared to the DA group,with statistically sig nificant differences(P<0.05).Conclusion SPP1 and MYD88 play critical roles in mediating morphine-induced cardiomyocyte apoptosis,and silencing SPP1 has been shown to significantly reduce the extent of cardiomyocyte apoptosis following morphine exposure.

Objective To explore the role of secreted phosphoprotein 1(SPP1)and myeloid differentiation primary response 88(MYD88)in morphine-induced cardiomyocyte apoptosis.Methods A morphine addiction model was established in Sprague-Dawley(SD)rats.Twelve SD rats were randomly assigned to the normal saline(NS)group or the morphine-dependent(DAM)group.Histopathological analysis was employed to observe and compare myocardial tissue morphology between the two groups.Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL)staining was performed to assess the number of apoptotic cells in each group.The expression levels of SPP1 and MYD88 were evaluated using immunohistochemistry.Quantitative real-time poly merase chain reaction(RT-qPCR)and Western blot were used to detect the mRNA and protein expression of SPP1,MYD88,Bax,Bcl2,Caspase-3,and Caspase-9.Simultaneously,Western blot analysis was used to detected the expression of Cleaved Caspase-3 and Cleaved Caspase-9 proteins.In vitro,SPP1 expression was knocked down in primary neonatal rat cardiomyocytes(NRCMs),and cells were divided into three groups:control(CON),morphine treated(DA),and shSPP1#3+DA.Cell viability was assessed using the CCK-8 assay,and apoptosis rates were determined by flow cytometry.Results HE and TUNEL staining of myocardial tissues from morphine-addicted SD rats revealed that,compared with the NS group,myofibrils in the DAM group exhibited partial disruption and a significant increase in apoptotic cells(P<0.05).Western blot and RT-qPCR analyses demonstrated that,relative to the NS group,the mRNA and protein levels of SPP1,MYD88,Bax,Caspase-3,and Caspase-9 were significantly upregulated in the DAM group(P<0.05),whereas Bcl2 expression was significantly downregulated at both mRNA and protein levels(P<0.05),and the protein expression levels of Cleaved Caspase-3 and Cleaved Caspase-9 were also increased.with all differences being statistically significant.In NRCMs following morphine intervention,cell viability in the DA group was markedly reduced compared to the CON group(P<0.05),accompanied by a signifi-cant increase in apoptosis rate(P<0.05).Consistently,Western blot and RT-qPCR results showed elevated mRNA and protein expression of SPP1,MYD88,Bax,Caspase-3,and Caspase-9 in the DA group(P<0.05),along with decreased Bcl2 expression(P<0.05).The protein expression levels of Cleaved Caspase-3 and Cleaved Caspase-9 were elevated simultaneously.In contrast,the shSPP1#3+DA group exhibited opposing trends compared to the DA group,with statistically sig nificant differences(P<0.05).Conclusion SPP1 and MYD88 play critical roles in mediating morphine-induced cardiomyocyte apoptosis,and silencing SPP1 has been shown to significantly reduce the extent of cardiomyocyte apoptosis following morphine exposure.