Thymosin beta-4 (Tβ4) is a water-soluble, 43-amino acid, and 4.9 kDa protein that was originally isolated from bovine thymus . Since Tβ4 is the major actin-sequestering molecule in eukaryotic cells and is found in all cells , Tβ4 has multiple diverse cellular functions, including tissue development, migration, angiogenesis, and wound healing . We previously reported that Tβ4-overexpressing transgenic mice, using a construct on the skin-specific keratin-5 promoter, have abnormal tooth development and enhanced stimulation of hair growth . Moreover, exogenous Tβ4 has anti-inflammatory effects in the bleomycin-induced mouse model of lung fibrosis , tooth extraction sockets in rats , rat model of myocardial ischemia , corneal wound healing , wound healing of rat palatal mucosa , in vitro model of cultured human gingival fibroblasts , and cardiac fibroblasts . However, the effects of Tβ4 over expression or inhibition on differentiation are controversial. Exogenous β4 peptide inhibited osteogenic differentiation but facilitated adipogenic differentiation in human bone marrow-derived-mesenchymal stem cells (MSCs) . In contrast, Tβ4 inhibition by Tβ4 siRNA attenuated odontoblastic differentiation in the odontoblast-like cells, MDPC-23 . Moreover, we recently demonstrated that odontoblastic differentiation was enhanced by activation of Tβ4 by Tβ4 peptide but was decreased by Tβ4 siRNA in human dental pulp cells (HDPCs) . However, the effects of Tβ4 on osteoclastic differentiation have not been reported.
In the experiments, an epithelial wound was made in the corneas of sedated rats. A Tb4 solution was applied at several concentrations to the injured eyes in one group of rats while another group was treated with a solution without Tb4. Following 12, 24 and 36 hours, the eyes were tested by microscopic observation for epithelial growth over the injured site. Investigators found the Tb4 accelerated corneal wound repair at doses of Tb4 similar to those found to repair skin wounds. When tested 24 hours after treatment, the rate of accelerated repair was proportional to the concentration of Tb4, with the highest dose (25 microgram) showing a threefold acceleration of epithelial cell migration, compared to untreated. Treatment with Tb4 showed anti-inflammatory effects, helping resolve the injury. An application to human cells in a model of human corneal cells in culture showed that Tb4 enhanced epithelial cell migration in vitro.
Consult a health care practitioner if symptoms persist or worsen. Consult a health care practitioner prior to use: if you are pregnant or breastfeeding; if you are taking carbidopa or drugs/supplements with serotonergic activity including, but not limited to, L-tryptophan, S-adenosylmethionine (SAMe), St. John's Wort, antidepressants, pain killers, over-the-counter cough and cold medication containing dextromethorphan, anti-nausea medication and anti-migraine medication. Discontinue use and consult a health care practitioner if you show signs of weakness, oral ulcers, or abdominal pain accompanied by severe muscle pain. Do not use if you have scleroderma. Exercise caution if operating heavy machinery, driving a motor vehicle or involved in activities requiring mental alertness. Some people may experience diarrhea, nausea, vomiting, abdominal pain and drowsiness.