黄芪甲苷通过调控miR-340-5p、SMAD2表达对盆底功能障碍大鼠的保护机制研究OA

AIM:To investigate the protective ef-fect of astragaloside IV(ASIV)in pelvic floor dys-function(PFD)rats and its effect on the expression of microRNA(miR)-340-5p and Smad homolog 2(SMAD2).METHODS:PFD rat model was construct-ed.The successfully modeled rats were randomly divided into the PFD group,the ASIV-L group,the ASIV-M group,the ASIV-H group,the ASIV-H+miR-NC group,and the ASIV-H+miR-340-5p mimics group,with 12 rats in each group.Another 12 nor-mal healthy rats were taken as the Control group.The relevant indicators such as pelvic floor function,urodynamics(bladder volume,intravesical pressure,leak point pressure),and mean myoelectric poten-tial of muscle fibers of rats in each group were de-tected.HE staining and Masson staining were used to observe the pathological changes of the levator ANI muscle tissue.Immunohistochemical detection of the relative expressions of type Ⅰ Collagen(Col-lagen Ⅰ)and Elastin.qRT-PCR was used to detect the level of miR-340-5p.Western blot was used to detect the relative expression of SMAD2.The dual-luciferase reporter gene system was used to verify the targeting relationship between miR-340-5p and SMAD2.RESULTS:Compared with the Control group,the levator ani muscle in the PFD group ex-hibited hypertrophy,with atrophied cells and the presence of mast cells within the muscle fiber tis-sue.A large number of muscle fibers showed necro-sis and disorganized arrangement.A small amount of blue collagen fibers was observed,and the over-all muscle fiber content was significantly reduced(P<0.05).Bladder volume,intravesical pressure,leak point pressure,vaginal resting pressure,vagi-nal squeeze pressure,and the mean myoelectric po-tential of type Ⅰ and type Ⅱ muscle fibers were all decreased(P<0.05).The relative expressions of Col-lagen Ⅰ,Elastin,and protein SMAD2 were also de-creased,while the bladder neck range of motion,urethral rotation angle,and relative level of miR-340-5p were increased(P<0.05).Compared with the PFD group,the ASIV-L,ASIV-M,ASIV-H,and ASIV-H+miR-340-5p mimics groups showed markedly im-provements in muscle fiber tissues,with reduced necrosis,no apparent degeneration,and more or-derly arranged fibers.Collagen fiber content in-creased to varying degrees,and the overall muscle fiber content was elevated(P<0.05).Bladder vol-ume,intravesical pressure,leak point pressure,vaginal resting pressure,vaginal squeeze pressure,and the mean myoelectric potential of type Ⅰ and type Ⅱ muscle fibers were increased(P<0.05).The relative expressions of Collagen Ⅰ,Elastin and SMAD2 were also upregulated,whereas the blad-der neck range of motion,urethral rotation angle,and relative level of miR-340-5p were decreased(P<0.05).In the ASIV-H+miR-340-5p mimics group,muscle fiber histopathological damage was more severe than in the ASIV-H,and ASIV-H+miR-NC groups,with a significant reduction in collagen fibers.Bladder volume,intravesical pressure,leak point pressure,vaginal resting pressure,vaginal squeeze pressure,and the mean myoelectric poten-tial of type Ⅰ and type Ⅱ muscle fibers were de-creased(P<0.05).The relative expressions of Colla-gen Ⅰ,Elastin and SMAD2 were decreased,while the bladder neck range of motion,urethral rotation angle and relative level of miR-340-5p were in-creased(P<0.05).Analysis using the Starbase database and dual-luciferase gene report assays in-dicated that miR-340-5p targeted and inhibited SMAD2 expression.CONCLUSION:ASIV improves PFD in rats through downregulation of miR-340-5p and upregulation of SMAD2.