ABSTRACT
This study aimed to observe the effect of terpinen-4-ol(T4O) on the proliferation of vascular smooth muscle cells(VSMCs) exposed to high glucose(HG) and reveal the mechanism via the Krüppel-like factor 4(KLF4)/nuclear factor kappaB(NF-κB) signaling pathway. The VSMCs were first incubated with T4O for 2 h and then cultured with HG for 48 h to establish the model of inflammatory injury. The proliferation, cell cycle, and migration rate of VSMCs were examined by MTT method, flow cytometry, and wound healing assay, respectively. The content of inflammatory cytokines including interleukin(IL)-6 and tumor necrosis factor-alpha(TNF-α) in the supernatant of VSMCs was measured by enzyme-linked immunosorbent assay(ELISA). Western blot was employed to determine the protein levels of proliferating cell nuclear antigen(PCNA), Cyclin D1, KLF4, NF-κB p-p65/NF-κB p65, IL-1β, and IL-18. The KLF4 expression in VSMCs was silenced by the siRNA technology, and then the effects of T4O on the cell cycle and protein expression of the HG-induced VSMCs were observed. The results showed that different doses of T4O inhibited the HG-induced proliferation and migration of VSMCs, increased the percentage of cells in G_1 phase, and decreased the percentage of cells in S phase, and down-regulated the protein levels of PCNA and Cyclin D1. In addition, T4O reduced the HG-induced secretion and release of the inflammatory cytokines IL-6 and TNF-α and down-regulated the expression of KLF4, NF-κB p-p65/NF-κB p65, IL-1β, and IL-18. Compared with si-NC+HG, siKLF4+HG increased the percentage of cells in G_1 phase, decreased the percentage of cells in S phase, down-regulated the expression of PCNA, Cyclin D1, and KLF4, and inhibited the activation of NF-κB signaling pathway. Notably, the combination of silencing KLF4 with T4O treatment further promoted the changes in the above indicators. The results indicate that T4O may inhibit the HG-induced proliferation and migration of VSMCs by down-regulating the level of KLF4 and inhibiting the activation of NF-κB signaling pathway.
Subject(s)
NF-kappa B/metabolism , Interleukin-18/metabolism , Proliferating Cell Nuclear Antigen/genetics , Cyclin D1/metabolism , Tumor Necrosis Factor-alpha/metabolism , Muscle, Smooth, Vascular , Cell Proliferation , Signal Transduction , Cytokines/metabolism , Glucose/metabolismABSTRACT
0.05).IL-4 in group S0 was significant higher than that in group C(t=11.65 P