模拟失重大鼠胸主动脉和腹主动脉S1P/S1PRs通路改变

目的研究四周模拟失重对大鼠胸主动脉(TA)和腹主动脉(AA) 1-磷酸鞘氨醇(S1P)及其受体(S1PRs)蛋白表达和分布的影响。方法 SD大鼠28只,随机分为对照(CON)组和悬吊(HU)组,每组14只(n=14)。采用尾部悬吊建立大鼠模拟失重模型,时间为4周。苏木精-伊红(HE)染色观察动脉的结构变化,Western blot和免疫组织化学染色检测神经鞘氨醇激酶(Sph K) 1和Sph K2、S1P裂解酶(SGPL) 1、1～3型S1PRs(S1PR1、S1PR2、S1PR3)、增殖细胞核抗原(PCNA)和I型胶原蛋白(COL1)的蛋白表达和分布变化。结果悬吊4周后,与CON组相比,HU组TA的Sph K1表达无明显改变,而Sph K2和SGPL1表达降低(P <0. 05),S1PRs表达和分布均无明显改变;同时,与CON组相比,HU组大鼠TA内-中膜厚度(IMT)和横截面积(CSA)增加,PCNA表达显著增加(P <0. 05),但COL1表达无明显变化。与TA不同,与CON组比较,四周尾部悬吊后AA的Sph K1、Sph K2与SGPL1表达显著增加(P <0. 05),S1PR1和S1PR3表达显著降低(P <0. 05),IMT、CSA和PCNA表达无显著变化,但COL1表达显著减少(P <0. 05)。此外,CON组AA的Sph K1、Sph K2、SGPL1、S1PR3、PCNA和COL1的蛋白表达均显著低于TA(P <0. 05),S1PR1蛋白表达则高于TA(P <0. 05),IMT与CSA均小于TA(P <0. 05)。结论模拟失重大鼠TA与AA的S1P合成和降解过程发生部位特异性改变,可能与其平滑肌细胞增殖程度有关; S1P及其受体含量在TA和AA间存在部位差异。

Remodeling of S1P/S1PRs in thoracic and abdominal aorta of simulated weightless rats

AIM AIM To observe the effects of simulated weightlessness on protein expressions and distribution of sphingosine-1-phosphate (S1P) and its receptor (S1PRs) in the thoracic aorta (TA) and abdominal aorta (AA) of rats. METHODS Hindlimb unloading tail suspension (HU) was performed in rats to simulate the effect of weightlessness on vascular system. Thoracic aorta (TA) and abdominal aorta (AA) were isolated and collected. Hematoxylin-eosin (HE) staining was conducted for evaluation of intima-media thickness (IMT) and cross section area (CSA). Western blotting and immunohistochemical staining were carried out to detect protein expressions and distribution of sphingosine kinase 1 (SphK1) and 2 (SphK2), S1P lyase 1 (SGPL1), S1P receptors (S1PR1, S1PR2 and S1PR3), proliferating cell nuclear antigen (PCNA) and collagen 1 (COL1). RESULTS After 4 weeks’ (wk) tail suspension, no significant changes were found in protein expressions of SphK1 and S1P receptors in TA, while those of SphK2 and SGPL1 decreased significantly (P<0.05). IMT, CSA and PCNA were significantly increased in TA of HU rats. In contrast to those in TA, protein expressions of SphK1, SphK2 and SGPL1 in AA significantly increased (P<0.05) in HU relative to control (CON), and those of S1PR1 and S1PR3 significantly decreased (P<0.05). No significant changes were found in IMT, CSA and PCNA content after tail suspension, but COL1 expression decreased significantly (P<0.05). Moreover, we found protein expressions of SphK1, SphK2, SGPL1, S1PR3, PCNA and COL1 were significantly higher and S1PR1 lower in TA than those in AA. CONCLUSION Simulated weightlessness results in regional-specific remodeling of synthesis and degradation of S1P in AA and TA. Besides, there is notable intrinsic discrepancy in S1P/S1PRs between AA and TA.