Study The Effect Of TLR4 Signal Pathway On Expression Of Autologous Arteriovenous Fistula

Objective Arteriovenous fistula(AVF)is the lifeline for maintenance hemodialysis(MHD)patients,and its dysfunction causes extremely distress to MHD patients.Therefore,this study explores the expression of toll-like receptor 4(TLR4)and nuclear factor-κB(NF-κB)in venous tissue of AVF stenotic,and investigates the relationship between the TLR4 signal pathway and vascular neointimal hyperplasia.It further elucidates the mechanism of TLR4 signal pathway involved in neointimal hyperplasia leading to AVF stenosis.It provides the new theoretical evidence for the prevention and treatment of AVF stenosis in the future.Methods This study collected discarded venous tissues from MHD patients who underwent AVF surgery for the first time and those who underwent AVF reconstruction due to fistula stenosis in the department of nephrology,Baotou Central Hospital,from September 2020 to December 2022.Preoperative upper limb vascular ultrasound examination indicated the presence of AVF stenosis,which was further confirmed during surgery.Two observation groups and one control group were established.Samples from the observation group A consisted of venous tissue from AVF stenosis in patients who underwent AVF reconstruction(n=16),and samples of the observation group B consisted of discarded venous tissue from patients who underwent AVF surgery for the first time(n=20).The control group C consisted of normal venous tissue from patients who underwent great saphenous varicose vein surgery in our general surgery department(n=10).Meanwhile,the general baseline data of patients in these groups were collected.Venous tissue samples from the three groups were embedded and stained with hematoxylin-eosin(HE)and Masson trichrome stain(Masson)to observe the morphological characteristics of venous tissues.And the intima/media thickness ratio of the three groups was also measured.Immunohistochemical staining was used to detect the expression of TLR4 and NF-κB in venous tissue.Statistical software SPSS 26.0(SPSS Inc,Chicago,USA)was used for analysis,and statistical analysis was performed with bilateral tests,and the significance test level was α = 0.05.Results This study included 46 patients,with 36 patients in the observation groups(16patients in the observation group A and 20 patients in the observation group B and 10 patients in the control group.HE and Masson trichrome staining showed that compared with the control group,patients who underwent AVF surgery for the first time and those who underwent AVF reconstruction due to stenosis had different degrees of neointimal hyperplasia and tube wall fibrosis in the venous tissues.The intima/media thickness ratios of the three groups were measured [0.76(0.34,1.02);0.19(0.14,0.24);0.18(0.11,0.20)].The statistical results showed that the intima/media thickness ratio of venous tissue in observation group A was significantly higher than that in the observation group B and the control group C(P<0.05),while difference between the observation group B and the control group C was insignificant(P=1.000).Immunohistochemical staining showed that TLR4 was mainly expressed in the cytoplasm and nuclear membrane of endothelial cells and smooth muscle cells,and NF-κB was mainly expressed in the cytoplasm and nuclei of endothelial cells and smooth muscle cells.Immunohistochemical staining showed that TLR4 was strongly positive in both the observation groups A [0.33(0.28,0.36)] and B [0.26(0.24,0.34)],and both groups were significantly different from the control group C [0.13(0.11,0.14)](P<0.05).However,there was no significant difference in the expression of TLR4 between observation group A and observation group B(P=0.208).The expression of NF-κB was strongly positive in the observation group A(0.46 ± 0.08),moderately positive in the observation group B(0.40 ±0.07),and weakly positive in the control group C(0.35 ± 0.04).The expression of NF-κB in the observation group A was significantly higher than that in the other two groups(P<0.05),while there was no significant difference between the observation group B and the control group C(P>0.05).The correlation analysis between TLR4 and NF-κB showed a positive correlation between the expression of TLR4 and NF-κB in the observation group A(r=0.521,P=0.039,<0.05),but no correlation was found in observation group B and control group C(r=0.035,P=0.882,>0.05;r =-0.007,P=0.985,>0.05).Conclusion 1.The activation and excessive activation of the TLR4 signal pathway may be involved in the pathological process of neointimal hyperplasia and fibrosis leading to AVF stenosis,and moderate expression may help promote fistula maturation,providing evidence-based medical for the prevention and treatment of AVF stenosis in the future.2.The expression of TLR4 and NF-κB were upregulated in AVF stenotic vein tissue,and there was a linear relationship between TLR4 and NF-κB,suggesting that the TLR4/NF-κB signaling pathway may play an important role in mediating neointimal hyperplasia and vessel wall fibrosis in stenotic AVF.