Expression And Purification Of Human Thioredoxin From E.coli And Its Protective Effect In A Murine Model Of Endotoxemia

Human thioredoxin(hTRX) is a 104 amino-acid protein with low molecular weight of 12 kDa. hTRX, in conjunction with TRXR and NADPH forms one of the main antioxidant enzyme systems in the body and has various important physiological functions including the activity regulation of some transcription factor, such as NFκB , AP-1 and GR, the stimulation of cell growth, and the inhibition of apoptosis and the ROS scanvenging. hTRX can protect cells and tissues against a variety of oxidative stress stimuli. In order to clarify the potential effect of hTRX on septic shock therapy, we purified recombinant hTRX protein expressed by E.coli, and confirmed that rhTRX can signifcantly promote the cell growth, inhibite apoptosis and had antioxidant activity. Moreover the stability of rhTRX in different storage and the change of its biological functions were observed. These results will facilitate the further studies in vivo.The death of mice induced by lethal dose of LPS (200 mg/kg) was absolutely prevented by injection 10 mg/kg of rhTRX protein. Further studies in vivo showed that rhTRX reduced the tissue damage and MDA level in serum and tissues, inhibited the production of TNF-α of serum and peritoneum and thymus apoptosis. In vitro, the extents of TNF- α and IL-6 production of murine macrophage in response to LPS were greately reduced by adding rhTRX (25 ug/ml and 50 ug/ml) at 30 min before , the same time or 30 min after LPS administration. It also proved that in vitro, rhTRX (25 ug/ml and 50 ug/ml) attenuated murine hepatocytes injury and MDA production by high dose of...