ABSTRACT
@#Objective Pulmonary vein banding was used to establish a piglet model of pulmonary vein stenosis. We investigated the pathomorphological alterations of pulmonary veins in the model and compared it with the vascular tissue of recurrent stenosis after total anomalous pulmonary venous connection (TAPVC). Methods Ten pigs of 6 weeks old were selected and randomly divided into 2 groups: 5 in a sham operation group and 5 in a pulmonary vein banding group. The operation had two stages, in which thoracotomies through intercostal space were done respectively on both sides. Biocompatible materials were applied around the pulmonary veins in the experimental group. The same method was used in the sham group. But the pulmonary veins were not banded. Six weeks after the operation, the pulmonary veins of the animals were harvested for hematoxylin-eosin staining and immunofluorescence staining to observe the pathological alterations of pulmonary veins. The proliferative tissues of patients with recurrent stenosis after TAPVC repair were collected and observed by hematoxylin-eosin staining and immunofluorescence staining. Results Both the sham operation group and the pulmonary vein banding group survived. But the pulmonary vein banding group had obvious clinical manifestations of pulmonary venous stenosis. Compared with the sham group, the pulmonary vein banding group showed intimal hyperplasia, decreased expression of endothelial marker and increased expression of mesenchymal markers, and co-expression of endothelial and mesenchymal markers in intimal cells. Human pathology also showed intimal hyperplasia and co-expression of endothelial and mesenchymal markers in intimal cells. Conclusion The surgical pulmonary vein stenosis in piglets shows intimal hyperplasia and myofibroblasts, which was consistent with clinical pathology.
ABSTRACT
@#Objective To study the impact of chronic hypoxia on white matter (WM) injury and brain development delay using a neonatal rat model, and to explore its value in simulating chronic hypoxic brain damage in cyanotic congenital heart disease (CHD). Methods Three-day-old Sprague-Dawley (SD) rats were randomly distributed to an experiment group (n=36, FiO2 10.5%±1.0%) and a control group (n=36, FiO2 21.0%±0.0%) and were raised for 12 days. (1) Body weight of SD rats was recorded every day and fresh brain weight was measured on P14. (2) H&E staining was performed on sections of brain tissue to observe pathological changes and ventricular size. (3) Immunohistochemistry (IHC) was applied to reveal alterations of oligodendroglial progenitor cells (OPC), preoligodendrocytes (PreOL) and myelin basic protein (MBP) in brain WM area. (4) Protein was extracted from 50 mg of brain tissue in WM area and expression of MBP was determined using Western blotting. (5) Motor function and coordination of rats (P30) were assessed via rotation experiment. Results (1) Body weight and brain weight were significantly less in the experiment group compared with the control group on P14 (body weight 14.92±1.26 gvs. 30.26±1.81 g, t=7.51, P<0.01; brain weight 0.68± 0.05 gvs.0.97±0.04 g, t=13.26, P<0.01); (2) HE staining: Sections of brain tissue from the experiment group showed ventricular size enlargement with a statistical difference (P<0.01), disordered cell organization, local neuronal death and leukomalacia. (3) The number of OPC and PreOL in the experiment group were significantly less than those in the control group (64.8±6.3vs. 126.2±8.4, t=11.19, P<0.01; 19.1±7.6vs. 46.7±9.5, t=7.28, P<0.01, respectively). MBP distribution was sparse and disorganized in the experiment group. (4) Western blotting: Expression of MBP was less in the experiment group (P<0.01). (5) Behavioral test: Time on rotarod was less in the experiment group with a statistical difference (P<0.01). Conclusion Chronic hypoxia can result in WM injury and brain development delay in neonatal rats, with features comparable to those seen in infants with cyanotic CHD.