DVT is a dynamic variation regulation network of complex disease with multiple factors, genes, systems involved in endothelial cells, platelets, coagulation-anticoagulation system, fibrinolytic-antifibrinolytic systems, hemorheology multiple systems, older age, trauma, surgery, brake, venipuncture, pregnancy, coagulation factor V of Leiden mutations, protein C, lack of anticoagulant enzyme Ⅲ, and prothrombin gene mutation genetic factors such 20210A. At present, the main clinical diagnosis can be clear and definite with the aid of DVT symptoms and signs, imageology and laboratory tests
[3]. The predictive diagnosis was mostly studied the markers on the molecular level, which is closely related to disease development, and the key of predictive diagnosis is to lock the specific genes or proteins for establishing effective detection methods and means.
KLF2 and KLF4 as the key factors and steady adjustment in vascular endothelial cells and important regulating factor in signal transduction pathways may be the important “molecular photoswitching” which adjust blood vessel function and thrombotic diseases. KLF2 and KLF4 can inhibit vascular inflammation and thrombosis, and their expression changes are likely closely related to thrombosis. Therefore, they might be molecular markers to predict the diagnosis of DVT.
Promote anticoagulation factor and inhibit coagulation factors
KLF2 and KLF4 play a role in inhibiting the formation of thrombosis, mainly through the transcriptional regulation of high expression of gene, and inhibiting the procoagulant genes expression. Lin et al[4] found that the over-expression of KLF2 can significantly induce high expression of TM and eNOS, and inhibit expression of cytokines medium which indued by TF.
Hamink et al[5-6] confirmed KLF4 was expression both in vitro and in vivo, which was induced by proinflammatory stimulation and shear stress. The over-expression of KLF4 can also induce expression of anticoagulation factors such as eNOS and TM. High expression of TM, can not only change protein C into activate protein C (APC) for strengthening its anticoagulation function, but also play a role in inhibiting prothrombin activating thrombin. KLF2 and KLF4 can also inhibit the secretion of coagulation factor vWF.
Inhibition of vascular inflammation and adhesion molecule on leukocyte
Inflammation is defensive responses when the body with vascular system relatives to injury factors. In the research of the pathogenesis of venous thrombosis, more and more scholars begin to pay close attention to the role of inflammatory mediators in DVT. Inflammation such as bacterial endotoxin or inflammatory cells factor can induce the expression of TF, and act on mononuclear macrophages stimulating blood clotting process. Many researchers have demonstrated that the up-regulation of KLF2 and KLF4 can inhibit the expression of inflammatory mediators such as IL-1β, IL-8, TNF-α, monocytes chemotactic protein-1 and macrophages inflammatory mediators-1 protein and T cells adhesion, monocytes activation in order to inhibit inflammation responses[7-9]. KLF2 and KLF4 can also inhibit leukocytes adhering to vascular endothelium[8], and adjust inflammation cell differentiation, migration and activation function suck as T cells, mononuclear-macrophage [9-11].
Inhibition of PAI-1 expression
KLF2 and KLF4 play a role in inhibition of the transcription and expression of PAI-1[12-14]. PAI-1 has a great resistant fibrinolysis ability, and can lose its activity when forms complexes with tissue plasminogen activator or urokinase-type plasminogen activator. PAI-1 also can be combined to endothelial surface to prevent excessive fibrinolysis. PAI-1 can inhibit the activity of thrombin, factor XIa, XIIa, kallikrein enzyme, and APC.
Inhibition of platelet activation and gather
KLF2 and KLF4 can promote expression of eNOS[4-6]. High expression of eNOS can induce the generation and release of nitric oxide, and combine with ornithine cyclodeaminase so as to increase the generation of cyclic guanosine monophosphate (cGMP), which inhibits platelet activation and gather.
Inhibition of endothelial proliferation and contraction
When the endothelial cells were given certain stimulation, KLF2 and KLF4 can regulate endothelial proliferation, angiogenesis and vasomotion, through the transcription regulation in order to regulate funtions of repairing the vascular damage, the flow velocity of blood, blood coagulation and hemostasis.
KLF2 promotes the expression of eNOS with KLF4, and can inhibit gene expression of endothelium, adrenaline and angiotensin converting enzyme, promote the expression of C-type natriuretic peptide and arginosuccinate synthetase[15-16]. Bhattacharya et al[17-18] demonstrated that over-expression of KLF2 can inhibit new angiogenesis and tissue oedema which mediated by vascular endothelial growth factor, weaken endothelial cell calcium flow which activated by VEGF, also inhibit cell proliferation and reduce the capacity of proinflammatory factor inducted by VEGF, also inhibit endothelial cell proliferation, migration and angiogenesis.
In this study, we applied real-time PCR to detect the expression changes of KLF2 and KLF4 in each groups, and the results showed that both Group B and Group C compared with Group A were significant differences in down-regulation expression (KLF2-BvsA: -1.510, CvsA: -2.889; KLF4-BvsA: -1.262, CvsA: -2.041), while Group D was significant difference in up-regulation (KLF2-DvsA: 1.224; KLF4-DvsA: 1.897). The study confirmed that the expression changes of KLF2 and KLF4 are closely related to DVT. KLF2 and KLF4 in group B and C which were differences in down-regulation expression, might impair the role of inhibiting vascular inflammation and anticoagulation, and contribute to thrombosis, while the expression of group D were significant difference in up-regulation, might promote anti-thrombotic effects and inhibit thrombosis. KLF2 and KLF4, which were differences in down-regulation expression in group B and C, up-regulation in group D, may be candidate molecular markers to predict the diagnosis of DVT in rats, but the regulation mechanisms needs further studies.
