Transforming growth factor-beta1 (TGF-β1) plays an important role on cardiac muscle differentiation, cardiac septa and valve formation during heart development. However, the role of TGF-β1 in cardiac valves of adult animals is largely unknown. Cardiac valves are target portion from repetitive, periodic and continuous physical loading in the body. Therefore, we examined the mRNA, protein levels, and protein distribution of TGF-beta1 in cardiac valves of adult animals to clarify the biological importance of TGF-β1.

Adult mice, rats and pigs were used. Cardiac valves of pig were frozen and were pulverized with liquid nitrogen. To measure the mRNA levels of TGF-β1 in cardiac valves, total RNA was extracted using Tri-reagent and performed Northern blot analysis. To measure the protein levels of TGF-β1 in cardiac valves, total protein was extracted and performed Western blot analysis. To examine the TGF-β1 distribution, immuno-histochemistry with anti-CC-1-30 antibody was performed.

The mRNA level of TGF-β1 in pulmonary valve was higher than those in the other valves. However, the protein levels of TGF-β1 were similar among valves. The mRNA and protein levels of TGF-β1 in cardiac valves were higher than those in atria or ventricles. The TGF-β1 protein was located mainly in cellular interstitium in cardiac valves. The distribution of TGF-β1 protein in surface area was higher than in the mid-portion of valves.

These results suggest that synthesis and distribution of TGF-beta1 in cardiac interstitum is essential for maintaining of normal structure and function on various physical loading.