FIG. 3.

Differential expression of elastin and elastin-associated proteins by ASMCs is influenced by ascorbate. (A) After 30 days of culture in the presence of 500 μM ascorbate, LV3 ASMCs exhibit a significantly reduced expression of tropoelastin mRNA relative to LV3 ASMCs cultured for the same period of time in the absence of ascorbate. The low levels of tropoelastin mRNA expressed by LX ASMCs are little affected by the presence or absence of ascorbate (n = 3), p < 0.05. (B) Desmosine levels, a measure of mature, crosslinked elastin, are very much higher in LV3 ASMCs compared with LX ASMCs and are significantly reduced in the presence of ascorbate (n = 3), p < 0.05. (C) mRNAs for the elastin-associated proteins fibulin-5 and fibrillin-1 are elevated in LV3 ASMCs compared with LX ASMCs, but LOX mRNA is similar or lower. For both LV3 and LX ASMCs, ascorbate reduced the levels of fibulin-5 and LOX mRNA, while increasing the levels of fibrillin-1 mRNA (p < 0.05). For each mRNA, values were normalized to the LX + ascorbate expression level. (D) In correspondence with levels of tropoelastin mRNA, ascorbate significantly reduces the mRNAs for the elastin-associated proteins fibulin-5 and LOX expressed by LV3 ASMCs (n = 3), p < 0.05. For each mRNA, values were normalized to the LV3 + ascorbate expression level. LOX, lysyl oxidase.