Effects of combined thymosin and hydrocortisone on immune response in septic mice.

This study is to investigate the effects of the thymosin α1 (Tα1) and hydrocortisone (HC) combination treatment on the immune responses in septic mice. According to different treatments, mice were divided into the control group (n = 18), the sepsis model group (n = 18), the Tα1 group (n = 18), the HC group (n = 18), and the Tα1+HC group (n = 18). Septic mouse model was established by the intraperitoneal injection of lipopolysaccharide (LPS). At 72 h after modeling, flow cytometry was used to analyze the dendritic cell (DC) numbers in peripheral blood and the expressions of MHC II and CD86. Tumor necrosis factor-α (TNF-α) level was measured by ELISA. Treatments of Tα1 and/or HC dramatically increased the survival rates of LPS-induced septic mice. Flow cytometry showed that, the DC numbers in peripheral blood were significantly decreased in the sepsis model group, which could be dramatically elevated by Tα1 treatment alone and in combination with HC (Tα1+HC). However, the DCs were undetectable in the HC group. In addition, the MHC II expression level was decreased in the sepsis model group, which was further declined in the Tα1 and Tα1+HC groups. The expression level of CD86 was elevated in the model group, which could be significantly down-regulated by the treatments of Tα1 and Tα1+HC. ELISA showed that, the peripheral blood TNF-α level in the HC group was lower than in the sepsis model group. Compared with the sepsis model group, the TNF-α levels were significantly elevated in the Tα1 and Tα1+HC groups. Tα1 and HC combination treatment could improve the immune function and regulate the inflammatory response to increase the survival rates of LPS-induced septic mice.