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Objective To elucidate the characteristics of vascular remodeling in pregnant hypertensive rats.Methods Pregnant rats were induced by L-nitro-arginine methylester (L-NAME) to build hypertension models and normal pregnant rats were used as control.Using a programmable sphygmomanometer,the blood pressure was recorded with the tail-cuff method to ensure the hypertension model was successfully replicated.The changes of mean shear stress were determined after the blood viscosity,the average blood flow and the inner diameter in left common carotid artery were measured.To analyze the degree of arterial remodeling,the protein expression levels of collagen Ⅰ (Col Ⅰ) and Ⅲ (Col Ⅲ) were detected by Western blotting,and the media thickness,the inner diameter,the opening angel both in thoracic aorta and carotid artery were determined.Results The mean shear stress of common carotid artery was reduced by (28.52 ± 3.08) ％ with the blood viscosity increasing and the average blood flow decreasing in pregnant hypertensive rats.Compared with control groups,the ratio of media thickness and inner diameter significantly increased in thoracic aorta and carotid artery,while the opening angel decreased in carotid artery and increased in thoracic aorta.With the expression of Col Ⅰ decreasing and Col Ⅲ increasing,the ratio of Col Ⅰ and Col Ⅲ went an apparent decline.Conclusions The mean shear stress is descending in pregnant hypertensive rat,with the remodeling of thoracic aorta and carotid artery.These results may provide new experimental references for further illustrating pathogenesis of pregnant hypertension.
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Objective To elucidate the characteristics of vascular remodeling in pregnant hypertensive rats.Methods Pregnant rats were induced by L-nitro-arginine methylester (L-NAME) to build hypertension models and normal pregnant rats were used as control.Using a programmable sphygmomanometer,the blood pressure was recorded with the tail-cuff method to ensure the hypertension model was successfully replicated.The changes of mean shear stress were determined after the blood viscosity,the average blood flow and the inner diameter in left common carotid artery were measured.To analyze the degree of arterial remodeling,the protein expression levels of collagen Ⅰ (Col Ⅰ) and Ⅲ (Col Ⅲ) were detected by Western blotting,and the media thickness,the inner diameter,the opening angel both in thoracic aorta and carotid artery were determined.Results The mean shear stress of common carotid artery was reduced by (28.52 ± 3.08) ％ with the blood viscosity increasing and the average blood flow decreasing in pregnant hypertensive rats.Compared with control groups,the ratio of media thickness and inner diameter significantly increased in thoracic aorta and carotid artery,while the opening angel decreased in carotid artery and increased in thoracic aorta.With the expression of Col Ⅰ decreasing and Col Ⅲ increasing,the ratio of Col Ⅰ and Col Ⅲ went an apparent decline.Conclusions The mean shear stress is descending in pregnant hypertensive rat,with the remodeling of thoracic aorta and carotid artery.These results may provide new experimental references for further illustrating pathogenesis of pregnant hypertension.
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Objective To elucidate the characteristics of vascular remodeling in pregnant hypertensive rats. Methods Pregnant rats were induced by L-nitro-arginine methylester (L-NAME) to build hypertension models and normal pregnant rats were used as control. Using a programmable sphygmomanometer, the blood pressure was recorded with the tail-cuff method to ensure the hypertension model was successfully replicated. The changes of mean shear stress in left common carotid artery were determined after the blood viscosity, the average blood flow and the inner diameter were measured. To analyze the degree of arterial remodeling, the protein expression levels of Collagen I (Col I) and III (Col III) were detected by Western blotting and the media thickness, the inner diameter, the opening angel were determined in both thoracic aorta and carotid artery. Results The mean shear stress of common carotid artery in pregnant hypertensive rats was reduced by (28.52 ± 3.08)% with the blood viscosity increasing and the average blood flow decreasing in pregnant hypertensive rats. Compared with control groups, the ratio of media thickness and inner diameter was significantly increased in thoracic aorta and carotid artery, while the opening angel decreased in carotid artery while increased in thoracic aorta. With the expression of COL I decreasing and COL III increasing, the ratio of Col I and Col III went an apparent decline. Conclusions The mean shear stress is descending, and the remodeling of thoracic aorta and carotid artery are found in pregnant hypertensive rats. These results may provide new experimental references for further illustrating the pathogenesis of pregnant hypertension.
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Objective To investigate the effect of pathologically elevated cyclic strain induced by hypertension on proliferation of vascular smooth muscle cells (VSMCs) and the role of long non-coding RNA (IncRNA)-XR007793 during this process. Methods Flexcell-4000 tension system was used to apply physiologically (5% magnitude) and pathologically (15% magnitude) cyclic strain with frequency of 1.25 Hz on VSMCs for 24 h respectively. qRT-PCR was used to detect the expression of XR007793 and 4 co-expressed genes: signal transducer and activator of transcription 2 (STAT2), cell division cycle associated 8 (CDCA8), proto-oncogene LMO2 and interferon regulatory factor (IRF7). Western blot was used to detect the proliferating cell nuclear antigen (PCNA) level in VSMCs. RNA inference was used to inhibit XR007793 expression. The cell cycle of VSMCs was measured by flow cytometry in static condition and the cell proliferation was detected by Brdu-Elisa in cyclic strain loading condition. Results Compared with 5% cyclic strain, 15% cyclic strain remarkably decreased the XR007793 level and increased the proliferation of VSMCs，along with the increasing expression of STAT2 and CDCA8. XR007793 specific siRNA transfection under static condition decreased the expression of XR007793 and increased the VSMC proliferation. Under 15% cyclic strain, XR007793 specific siRNA transfection also increased the VSMC proliferation and the expression of CDCA8 compared with the non-specific siRNA control. Conclusions Pathologically elevated cyclic strain decreases the XR007793 expression level and increases the CDCA8 expression level to modulate VSMC proliferation. These results provide new experimental evidence for the study of mechanobiological mechanism during hypertension and potential targets for hypertension therapy.
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Objective To investigate the role of microRNA-34a (miR-34a) in the proliferation of vascular smooth muscle cells (VSMCs) induced by low shear stress (LowSS). Methods Using co-culture parallel plate flow chamber system, endothelial cells (ECs) and VSMCs were co-cultured and applied with normal shear stress (1.5 Pa) and LowSS (0.5 Pa) for 12 h. The expression of proliferating cell nuclear antigen (PCNA) in the co-cultured VSMCs was detected by Western blotting to determine the proliferation capacity of VSMCs. Real-time PCR was used to examine the miR levels of miR-34a in the co-cultured VSMCs. The target proteins of miR-34a were predicted by TargetScan, miRWalk and some other websites. Western blotting was used to detect expression of Forkhead box j2 (Foxj2) in the co-cultured VSMCs. Mimics and inhibitor were used to up-regulate or inhibit the expression of miR-34a, and then the expression of Foxj2 and PCNA was detected by Western blotting to verify the regulation relationship between miR 34a and Foxj2. Results Compared with NSS, LowSS promoted the PCNA expression and significantly up-regulated the miR-34a expression in the co-cultured VSMCs. Foxj2 was predicted to be the downstream target protein of miR-34a by TargetScan, miRWalk and some other websites. Foxj2 expression decreased significantly in the co-cultured VSMCs under LowSS application. Under static condition, the expression of Foxj2 obviously decreased and the expression of PCNA obviously increased by up-regulating miR-34a expression in VSMCs. While inhibiting the expression of miR-34a in VSMCs would result in a significant increase in the expression of Foxj2 and a significant decrease in the expression of PCNA. Conclusions LowSS can promote the proliferation of VSMCs by regulating miR-34a and target protein Foxj2 in the co-cultured VSMCs. This research finding will provide new mechanobiological experimental reference for further illustrating the pathogenesis of atherosclerosis and finding the therapeutic targets for drugs.
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Objective To investigate the regulating effect and mechanism of microRNA-21 (miR-21) on extracellular matrix (ECM) of vascular smooth muscle cells (VSMCs) by vascular remodeling of hypertension. Methods By narrowing the abdominal aorta in rats, the hypertension models were established and divided into 2-week hypertension group and 4-week hypertension group, and sham-operated group was also established as control. VSMCs from the rat aorta were subjected to 0% (static), 5% (normal) and 15%（hypertensive）elongation strain at a constant frequency of 1.25 Hz and duration of 12 hours, respectively. The expressions of Smad 7 and ECM were detected by Western blotting, and the expression of miR-21 was examined by Real-time RT-PCR. Finally, miR-21 siRNA was used to study the role of miR-21 in the mechanical strain-induced expression of ECM, miR-21 and Smad 7. Results Compared with the sham-operated group, ECM and miR-21 in thoracic aorta of 2-week hypertension group were significantly elevated. Collagen I, collagen III and miR-21 in thoracic aorta of 4-week hypertension group were significantly elevated. Compared with the static and 5% strain groups, the protein expression of collagen I in VSMCs did not show significant change, but the protein expression of collagen III was significantly elevated and Smad 7 expression was significantly decreased in 15% strain group. The cyclic strain also enhanced miR-21 expression in VSMCs. miR-21 inhibitor effectively decreased the expression of miR-21 in VSMCs and protein level of collagen III, while enhanced Smad 7 expression under the static and 15% strain. Conclusions The vascular remodeling of hypertension causes the high expressions of ECM and miR-21. The cyclic strain induces the high expression of miR-21, which via Smad 7 results in enhancing the expression of ECM, collagen III especially, in VSMCs under vascular remodeling of hypertension.
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Objective To investigate the effects of shear stress and vascular smooth muscle cells (VSMCs) on the proliferation of endothelial cells (ECs) and the molecular mechanism involved in. Method Using parallel-plate flow chamber system, normal shear stress of 15 dyn/cm2(1 dyn=10-5 N) was applied to ECs cultured singly and co cultured with VSMCs respectively. Then, the expression of PCNA, a molecule representing cell proliferation ability, and phosphorylation of Akt were analyzed by Western blotting in order to investigate the roles of shear stress and VSMCs in EC proliferation. Under the static condition, the expressions of PCNA and p-Akt were analyzed in ECs co-cultured with VSMCs with and without physical contact. And then TGFβ1 neutralizing antibody was employed to demonstrate the contribution of TGFβ1 in VSMCs induced EC proliferation. Results Normal shear stress decreased EC proliferation and Akt phosphorylation. VSMCs increased EC proliferation and Akt phosphorylation in both co-culture conditions with and without physical contact. Normal shear stress partly reversed the increase of proliferation and Akt phosphorylation in ECs with physical contact to VSMCs, and TGFβ1 neutralizing antibody exerted the similar effects in ECs without physical contact to VSMCs. Conclusions Normal shear stress is a protective factor with its inhibitory effect on EC proliferation. VSMCs induced EC proliferation via TGFβ1 and p Akt pathways by paracrine model.