Expression And Significance Of NGF And Its Receptor In Anterior Vaginal Wall Of Patients With Pelvic Organ Prolapse

Pelvic organ prolapse(POP)is a group of gynecological diseases,which is mainly caused by the disconnection of pelvic organs from their original anatomical position because of the weakness of pelvic floor muscles and fascia,including uterine prolapse,cystocele,urethrocele,rectocele,and so on.POP has a serious impact on women's physical and mental health,interpersonal relations,sexual life and so on.The exact pathogenesis is not clear.The high risk factors of pelvic floor supporting structure injury mainly include pregnancy,vaginal delivery,age,constipation,chronic cough,obesity,congenital malformation,etc.However,the exact mechanism of the injury is not clear,which may include the injury of muscles,collagen connective tissue,nerve and blood vessels which provide supporting force.In recent years,with the indepth understanding of the risk factors of pelvic floor dysfunction,the neural damage mechanism of pelvic floor support structure has become a new research hotspot.It has been confirmed that there were injury of pelvic floor nerve and abnormality of peptide neurotransmitter in POP,and there was a general phenomenon of denervation in pelvic floor muscle,which reveals that the mechanism of injury of pelvic floor nerve is related to the occurrence and development of POP.Nerve growth factor(NGF)is one of the members of the neurotrophic factor family,which has a stable role in regulating synaptic signal transmission.It plays an important role in the survival,differentiation,growth,repair and regeneration of neurons in different periods.According to the binding ability of NGF surface glycoprotein to lectin,it can be divided into high affinity tyrosine kinase A(TrkA)and low affinity p75 neurotrophin receptor(p75NTR).TrkA generally mediates positive signals,such as promoting the growth of nerve cells,while p75NTR mainly induces apoptosis of nerve cells.They have their own signaling pathways,but when they are co expressed,they influence each other and produce different biological effects.ObjectiveThis study examined the expression of NGF,p75NTR,and TrkA in the anterior vaginal wall,explored their relationship with POP,and provided new ideas for their diagnosis,treatment and early prevention.Materials and Methods1.Research objectSelected 30 cases of POP patients without SUI from January 2019 to October 2019 in the gynecological ward of the Third Affiliated Hospital of Zhengzhou University,all patients did the anterior vaginal wall repair or anterior pelvic floor reconstruction.According to the score of POP-Q,the patients were divided into two groups,14 in the group of POP-Q ? degree and 16 in the group of POP-QIII-? degree;At the same time,20 cases of non cancerous and non pelvic floor dysfunction(PFD)patients of the same period who did the total hysterectomy were taken as the control group.There was no significant difference in the general data of each group(P>0.05).All the selected patients were postmenopausal(menopausal years ?2 years),no systemic hormone drugs,no neurological and respiratory diseases,connective tissue diseases,functional ovarian tumors,etc.Approved by the Ethics Committee of the Third Affiliated Hospital of Zhengzhou University(2019 No.15),the patient signed an informed consent before surgery,and a full-thickness tissue of the anterior vaginal wall of a similar site was taken during surgery,about 1.0cm×1.0cm in size.2.experimental methodRT-PCR was used to detect the mRNA expression levels of NGF,p75NTR,and TrkA in the anterior vaginal tissue.Immunohistochemical staining was used to detect the protein localization and expression of NGF,p75NTR,and TrkA.3.Statistical analysisSPSS 21.0 software was used for statistical analysis.The measured data were normally distributed and expressed as mean ± standard deviation(x ± s).The T-test of two independent samples was used for group comparison.P<0.05 was statistically significant.Results1.General information of patients:The control group,POP-Q ? degree group and POP-Q ?-? degree group.The age,parity,BMI,and menopause time of the three groups were compared,and the differences were not statistically significant(P>0.05).2.RT-PCR results The mRNA expression levels of NGF,p75NTR,and TrkA in the control group were 0.98±0.08,0.85±0.06,0.92 ± 0.08;in the POP-Q ? degree group,they were 0.47±0.07,0.79±0.05,and 0.43 ± 0.04;POP-Q ?-? degree group was 0.41±0.03,0.53 ± 0.04,0.25± 0.19,the difference was statistically significant(P<0.05).The mRNA expression levels of NGF,p75NTR and TrkA in the anterior vaginal tissue of POP patients were less than those in the control group.3.The results of RT-PCR showed that the ratio of p75NTR/TrkA in the control group,POP-Q ? group and POP-Q?-? group was 0.92,1.84,2.12,respectively.The ratio of p75NTR/TrkA in the POP group was higher than that in the control group.4.Immunohistochemical results NGF staining in the anterior vaginal tissue was reddish brown,p75NTR and TrkA were brown.ImageJ software was used to determine the positive percentage of immunohistochemical staining results at low magnification(×100).The positive percentages of NGF,p75NTR and TrkA in the control group were 6.59±0.55,6.04±0.68,6.44±0.48;POP-Q ? group was 4.93 ±0.55,5.17±0.46,4.50±0.54;POP-Q ?-? group was 2.82±0.32,4.17±0.41,2.15±0.48,the difference was statistically significant(P<0.05).ConclusionThe expression of NGF and its receptor p75NTR and TrkA decreased in the anterior vaginal wall of POP patients,and the change of p75NTR/TrkA ratio indicated that there may be a decrease of nerve fibers and related neuropeptides in the anterior vaginal wall of POP patients,NGF and its receptor may participate in the occurrence and development of POP.