Protective effect of thymosin fraction 5 in animals with experimentally induced uremia

Abstract

Background. Growth factors such as insulin-like growth factor, epidermal growth factor, and hepatocyte growth factor have been reported to be effective in the treatment of acute renal failure, but their effectiveness in chronic renal failure has not been reported. Thymosin, a glycoprotein extract obtained from calf thymus, is also known to have growth factor-like activity. In this study, we investigated the protective effect of thymosin fraction 5 (TF5), isolated from thymosin, in mice and rats with experimentally induced uremia.

Methods. Uremia was induced in mice by administering cis-Diammine-dichloroplatinum CDDP; 5 mg/kg, intraperitoneally once a week for 5 weeks. From the start of CDDP administration, mice in groups 1, 2 and 3, respectively, were given subcutaneous injections of saline or 1 mg/kg or 3 mg/kg of TF5 three times a week for 5 weeks. Uremia was induced in rats using the 5/6 renal ablation model. Rats in groups 1 and 2, respectively, were given subcutaneous injections of saline or 3 mg/kg of TF5 three times a week from the fifth to the twelfth week after removal of the right kidney, for a total of 8 weeks.

Results. In uremic mice, 6 weeks after the start of CDDP administration, serum urea nitrogen (SUN) levels were 40.1 ± 16.4, 20.6 ± 6.6, and 20.2 ± 5.3 mg/dl in groups 1, 2, and 3, respectively, and the level was significantly lower in groups 2 and 3 than in group 1 (P < 0.05). In the uremic rats, 13 weeks after the removal of the right kidney, SUN levels were 105.2 ± 20.1 and 82.9 ± 11.6 mg/dl in groups 1 and 2, respectively, and serum creatinine levels were 2.22 ± 0.89 and 1.56 ± 1.06 mg/dl in groups 1 and 2, respectively, with a significant difference in both SUN and serum creatinine between groups 1 and 2 (P < 0.05).

Conclusion. These results suggest the possibility that TF5 has a protective effect against progression of uremia.