ObjectiveTo investigate the mechanism by which Kangxian Yixin prescription regulates the circular RNA 0006719 （circ0006719）/microRNA 6852-5p （miR-6852-5p）/transforming growth factor-β₁ （TGF-β₁）/Smad axis to ameliorate myocardial fibrosis in rats with dilated cardiomyopathy （DCM） and angiotensin Ⅱ （Ang Ⅱ）-induced activation of cardiac fibroblasts （CFs）. MethodsA DCM rat model was established by administration of furazolidone. The rats were divided into normal group， model group， captopril （CAP， 10.1 mg·kg^-1·d^-1） group， and low-， medium-， and high-dose Kangxian Yixin prescription groups （0.9， 1.8， 3.6 g·kg^-1·d^-1）， with 15 rats in each group. After modeling， the treatment groups received corresponding drug solutions by gavage， whereas the normal and model groups received an equal volume of normal saline for 60 consecutive days. Echocardiography was used to measure left ventricular end-systolic diameter （LVESD）， left ventricular end-diastolic diameter （LVEDD）， left ventricular ejection fraction （LVEF）， and left ventricular fractional shortening （LVFS）. Transmission electron microscopy （TEM）， hematoxylin-eosin （HE） staining， and Masson staining were used to observe myocardial ultrastructure， pathological changes， and collagen deposition. Immunohistochemistry （IHC） was used to detect the protein expression of collagen type Ⅰ alpha 1 （Col1A1） and collagen type Ⅲ（Col Ⅲ） in myocardial tissue. Real-time quantitative polymerase chain reaction （Real-time PCR）， Western blot， and fluorescence in situ hybridization （FISH） were used to detect the expression and localization of circ0006719， miR-6852-5p， fibrosis-related molecules， and TGF-β₁/Smad pathway-related molecules in myocardial tissue and CFs. CFs from neonatal rats were isolated and cultured in vitro. Cell Counting Kit-8 （CCK-8） assay was used to determine the optimal concentration of Kangxian Yixin prescription for subsequent intervention. An Ang Ⅱ-induced CF activation model was established， and the cells were divided into normal group， Ang Ⅱ group， Ang Ⅱ+CAP group， Ang Ⅱ+Kangxian Yixin prescription group， and Ang Ⅱ+Kangxian Yixin prescription+miR-6852-5p inhibitor group. CF viability and fibrosis-related molecular expression were detected. RNA immunoprecipitation （RNA IP） and dual-luciferase reporter assays were used to verify the targeting relationship between circ0006719 and miR-6852-5p. ResultsCompared with the normal group， the model group showed significantly increased LVESD and LVEDD， significantly decreased LVEF and LVFS， aggravated myocardial ultrastructural and histopathological injury， and significantly increased collagen volume fraction （CVF） in myocardial tissue （P<0.01）. The expression of circ0006719， Col1A1 mRNA， Col ⅢmRNA， and Col1A1， Col Ⅲ， TGF-β₁， Smad3， and Smad4 proteins in myocardial tissue was significantly upregulated， whereas miR-6852-5p expression and Smad7 protein expression were significantly downregulated （P<0.01）. Compared with the model group， the CAP group and the high- and medium-dose Kangxian Yixin prescription groups showed varying degrees of improvement in cardiac function， myocardial fibrosis， circ0006719/miR-6852-5p expression， and TGF-β₁/Smad pathway-related indicators， with more pronounced improvements in the CAP group and the high-dose Kangxian Yixin prescription group （P<0.05， P<0.01）. In in vitro experiments， 2.0 g·L^-1 was determined as the optimal concentration of Kangxian Yixin prescription for subsequent intervention. Compared with the normal group， the Ang Ⅱ group showed significantly increased CF viability， significantly upregulated expression of circ0006719， Col1A1 mRNA， α-smooth muscle actin （α-SMA） mRNA， and Col1A1， α-SMA， TGF-β₁， Smad3， and Smad4 proteins in CFs， and significantly downregulated miR-6852-5p expression and Smad7 protein expression （P<0.01）. Compared with the Ang Ⅱ group， the Ang Ⅱ+CAP group and the Ang Ⅱ+Kangxian Yixin prescription group showed markedly decreased CF viability and fibrosis-related mRNA and protein expression， markedly increased miR-6852-5p expression， and markedly attenuated TGF-β₁/Smad pathway activation （P<0.05， P<0.01）. Compared with the Ang Ⅱ+Kangxian Yixin prescription group， the Ang Ⅱ+Kangxian Yixin prescription+miR-6852-5p inhibitor group showed significantly increased CF viability （P<0.01）， markedly increased expression of circ0006719， Col1A1 mRNA， and Col1A1， TGF-β₁， and Smad4 proteins in CFs， and markedly decreased miR-6852-5p expression （P<0.05， P<0.01）. RNA IP and dual-luciferase reporter assays showed a targeting binding relationship between circ0006719 and miR-6852-5p （P<0.01）. ConclusionKangxian Yixin prescription may alleviate myocardial collagen deposition and myocardial fibrosis， improve cardiac function in DCM rats， and inhibit Ang Ⅱ-induced abnormal activation of CFs. Its mechanism may be associated with downregulation of circ0006719， restoration of miR-6852-5p expression， and inhibition of the TGF-β₁/Smad pathway.

ObjectiveTo investigate the mechanism by which Kangxian Yixin prescription regulates the circular RNA 0006719 （circ0006719）/microRNA 6852-5p （miR-6852-5p）/transforming growth factor-β₁ （TGF-β₁）/Smad axis to ameliorate myocardial fibrosis in rats with dilated cardiomyopathy （DCM） and angiotensin Ⅱ （Ang Ⅱ）-induced activation of cardiac fibroblasts （CFs）. MethodsA DCM rat model was established by administration of furazolidone. The rats were divided into normal group， model group， captopril （CAP， 10.1 mg·kg^-1·d^-1） group， and low-， medium-， and high-dose Kangxian Yixin prescription groups （0.9， 1.8， 3.6 g·kg^-1·d^-1）， with 15 rats in each group. After modeling， the treatment groups received corresponding drug solutions by gavage， whereas the normal and model groups received an equal volume of normal saline for 60 consecutive days. Echocardiography was used to measure left ventricular end-systolic diameter （LVESD）， left ventricular end-diastolic diameter （LVEDD）， left ventricular ejection fraction （LVEF）， and left ventricular fractional shortening （LVFS）. Transmission electron microscopy （TEM）， hematoxylin-eosin （HE） staining， and Masson staining were used to observe myocardial ultrastructure， pathological changes， and collagen deposition. Immunohistochemistry （IHC） was used to detect the protein expression of collagen type Ⅰ alpha 1 （Col1A1） and collagen type Ⅲ（Col Ⅲ） in myocardial tissue. Real-time quantitative polymerase chain reaction （Real-time PCR）， Western blot， and fluorescence in situ hybridization （FISH） were used to detect the expression and localization of circ0006719， miR-6852-5p， fibrosis-related molecules， and TGF-β₁/Smad pathway-related molecules in myocardial tissue and CFs. CFs from neonatal rats were isolated and cultured in vitro. Cell Counting Kit-8 （CCK-8） assay was used to determine the optimal concentration of Kangxian Yixin prescription for subsequent intervention. An Ang Ⅱ-induced CF activation model was established， and the cells were divided into normal group， Ang Ⅱ group， Ang Ⅱ+CAP group， Ang Ⅱ+Kangxian Yixin prescription group， and Ang Ⅱ+Kangxian Yixin prescription+miR-6852-5p inhibitor group. CF viability and fibrosis-related molecular expression were detected. RNA immunoprecipitation （RNA IP） and dual-luciferase reporter assays were used to verify the targeting relationship between circ0006719 and miR-6852-5p. ResultsCompared with the normal group， the model group showed significantly increased LVESD and LVEDD， significantly decreased LVEF and LVFS， aggravated myocardial ultrastructural and histopathological injury， and significantly increased collagen volume fraction （CVF） in myocardial tissue （P<0.01）. The expression of circ0006719， Col1A1 mRNA， Col ⅢmRNA， and Col1A1， Col Ⅲ， TGF-β₁， Smad3， and Smad4 proteins in myocardial tissue was significantly upregulated， whereas miR-6852-5p expression and Smad7 protein expression were significantly downregulated （P<0.01）. Compared with the model group， the CAP group and the high- and medium-dose Kangxian Yixin prescription groups showed varying degrees of improvement in cardiac function， myocardial fibrosis， circ0006719/miR-6852-5p expression， and TGF-β₁/Smad pathway-related indicators， with more pronounced improvements in the CAP group and the high-dose Kangxian Yixin prescription group （P<0.05， P<0.01）. In in vitro experiments， 2.0 g·L^-1 was determined as the optimal concentration of Kangxian Yixin prescription for subsequent intervention. Compared with the normal group， the Ang Ⅱ group showed significantly increased CF viability， significantly upregulated expression of circ0006719， Col1A1 mRNA， α-smooth muscle actin （α-SMA） mRNA， and Col1A1， α-SMA， TGF-β₁， Smad3， and Smad4 proteins in CFs， and significantly downregulated miR-6852-5p expression and Smad7 protein expression （P<0.01）. Compared with the Ang Ⅱ group， the Ang Ⅱ+CAP group and the Ang Ⅱ+Kangxian Yixin prescription group showed markedly decreased CF viability and fibrosis-related mRNA and protein expression， markedly increased miR-6852-5p expression， and markedly attenuated TGF-β₁/Smad pathway activation （P<0.05， P<0.01）. Compared with the Ang Ⅱ+Kangxian Yixin prescription group， the Ang Ⅱ+Kangxian Yixin prescription+miR-6852-5p inhibitor group showed significantly increased CF viability （P<0.01）， markedly increased expression of circ0006719， Col1A1 mRNA， and Col1A1， TGF-β₁， and Smad4 proteins in CFs， and markedly decreased miR-6852-5p expression （P<0.05， P<0.01）. RNA IP and dual-luciferase reporter assays showed a targeting binding relationship between circ0006719 and miR-6852-5p （P<0.01）. ConclusionKangxian Yixin prescription may alleviate myocardial collagen deposition and myocardial fibrosis， improve cardiac function in DCM rats， and inhibit Ang Ⅱ-induced abnormal activation of CFs. Its mechanism may be associated with downregulation of circ0006719， restoration of miR-6852-5p expression， and inhibition of the TGF-β₁/Smad pathway.

Objective:To investigate the prediction value of observed to expected lung area to head circumference ratio (o/e LHR), measured at different gestational age with various methods, on indication for extracorporeal membrane oxygenation (ECMO) in fetuses with isolated left-sided congenital diaphragmatic hernia (CDH).Methods:Clinical data of 40 neonates who were diagnosed with left-sided CDH and treated in Guangzhou Women and Children's Medical Center were retrospectively collected from January 2017 to May 2021. The o/e LHRs were prenatally calculated using maximum diameter and tracing method at 22-24 and 31-33 weeks of gestation. According to whether the neonates had indications for ECMO after birth or not, they were divided into ECMO ( n=12) or non-ECMO group ( n=28). Differences in the o/e LHR and general situations between the two groups were analyzed using C hi-square test, independent sample t-test, and non-parametric Mann-Whitney U test. Binary logistic regression was used to analyze the influencing factors for ECMO requirement and receiver operating characteristic (ROC) curve was used to evaluate the value of o/e LHR in predicting the indication for ECMO. Results:Both maximum diameter and tracing method suggested that the o/e LHR at 31-33 gestational weeks was lower than that at 22-24 gestational weeks [maximun diameter method: 40.4 (32.9-51.5) vs 45.1 (36.3-53.4), Z=－2.48, P=0.013; tracing method: 38.6 (33.2-47.6) vs 44.1 (35.9-51.7), Z=－3.29, P=0.001]. There was no statistical difference in o/e LHR detected at the same gestational weeks between the two methods (both P>0.05). Binary logistic regression showed that o/e LHR measured at 31-33 gestational weeks using maximum diameter method was an independent protective factor for ECMO requirement ( OR=0.873, 95% CI: 0.790-0.965, P=0.008). ROC curve analysis showed that the area under the curve for evaluating the predictive value of o/e LHR for ECMO requirement was 0.830 with the sensitivity of 83.3% and the specificity of 71.4% when the cut-off value of o/e LHR at 31-33 gestational weeks was 38.195 measured by maximum diameter method. Conclusions:The o/e LHR measured at 31-33 weeks is lower than that at 22-24 weeks of gestation by both methods. The o/e LHR measured by maximum diameter method at 31-33 weeks of gestation may be useful for predicting the ECMO indication after birth but requiring comprehensive evaluation of clinical conditions due to its insufficient predicting power.