Thymosin Beta-4 is Cytoprotective in Human Gingival Fibroblasts

Thymosin beta 4 (Tb4) is a highly conserved protein found in all tissues, except erythrocytes. Until recently it had thought to be solely as the major G-actin sequestering molecule. Current investigations have identified it to be an endothelial cell chemo-attractant, an angiogenic stimulant, and an anti-apoptotic and anti inflammatory agent most notably in ocular, skin and heart tissue. OBJECTIVES: The aim of the current investigation was to examine the cytoprotective role of Tb4 on oral tissue using human gingival fibroblasts.  METHODS: The human gingival fibroblast cell line HGF-1 (ATCC CRL-2014) was cultured in medium containing 10% serum and then serum-starved. In one set of experiments gingival fibroblasts were treated with TNF-a or chlorhexedine with or without Tb4. Apoptosis was assayed colorimetrically using the ApoPercentage assay. Apoptotic cells were counted in digitally captured images. Apoptosis data was determined as mean number of apoptotic cells +/- SEM. In a second set of experiments gingival fibroblasts were cultured in 24-well plates and treated with either TNF-a chlorhexidine digluconate, Peridex , or carbamide peroxide with or without Tb4.  Cytotoxicity was assayed for lactate dehydrogenase (LDH) activity using a colorimetric LDH cytotoxicity assay kit. Statistical analysis was performed using the student's t-test with significance value of p < 0.05. RESULTS:  Tb4 was able to protect gingival fibroblasts from apoptosis induced by TNF-a or by chlorhexidine.  Additionally, Tb4 was able to protect gingival fibroblasts against the cytotoxic effects of common dental chemotherapeutics such as chlorhexidine digluconate, Peridex and carbamide peroxide. CONCLUSION: Because of its multifunctional roles in protecting cells against damage, Tb4 has significant potential for use in a mouth rinse with its combined antimicrobial, anti-inflammatory, anti-apoptotic, and cytoprotective properties.