Abstract
β-thymosins (TBs), isolated from various vertebrates and invertebrates, are highly conservative 5-kDa polar peptides. Thymosin β4 (TB4) is the most abundant peptide representing about 70% to 80% of the total TB content in mammalian tissues, while thymosin β10 (TB10) is a minority member of TBs in human, rat and mouse tissues. Recent studies have revealed that TBs are multifunctional peptides involved in cell migration, angiogenesis, wound healing, inflammation, morphogenesis and tumor metastasis. Nonetheless, there have been very few reports concerning TBs directly related to the fields of dental research or clinical dentistry. In this study, we investigated the effects of TB4 and TB10 on the healing process in tongue wounds, using 27 amino-acid partial synthetic peptides of those TBs.
After perforating rats' tongues using a punch biopsy instrument, the synthetic peptides were injected intraperitoneally into each rat at the time of perforation and every day thereafter for four days. Controls for the treatment received identical amounts of phosphate buffered saline in the same manner. Histological sections of Day2, Day3 and Day4 cases were processed, and stained with hematoxylin-eosin (H-E) and phosphotungstic acid hematoxylin (PTAH). The area of the wound (W) was histologically subdivided into tissue defect (D) area and granulation tissue (G) area by our definition, with reference to H-E and PTAH sections. Each area was calculated using computer-aided data analysis. The ratio of the D area divided by the total (T) area of the cross-section, D/T value (%), in the TB4- and TB10-treated groups was always significantly smaller than in controls. On the other hand, only for Day2 cases, G/T values in experimental groups were significantly higher than in controls. These results suggested that TBs may minimize tissue damage, probably by suppressing necrosis and/or apoptosis during the initial stage of the wound.
