Association between the transcriptional levels of Htr‑1a and tryptophan hydroxylase‑1 in the hippocampus and the antifatigue effects of leucine on rats with postoperative fatigue

Abstract

Leucine (Leu), a branched‑chain amino acid (BCAA), is widely used in clinical practice following severe burns, gastrointestinal surgery, trauma and sepsis. In the present study, the antifatigue effects of BCAAs on a postoperative fatigue (POF) rat model, induced by 70% intestinal resection, were investigated. Leu (16.5 g/l) was administered intraperitoneally at a dose of 18 ml/kg/day. The fatigue level and antifatigue effects of Leu were evaluated by open‑field testing on day 1, 3, 5 and 7 after surgery. In addition, mRNA specimens were extracted and measured using a quantitative polymerase chain reaction method. The open‑field test results indicated that Leu exhibited a significant antifatigue effect. The total distance travelled and the number of times the rats passed from the outermost grids of an open‑top case were greatly improved in the Leu treatment group when compared with the POF model group. With the exception of the normal group, the mRNA expression levels of Htr‑1a exhibited a similar trend in all other groups, reaching a climax on day 3 and 5, while being restored to a normal level on day 7. With regard to the Leu intervention group, the mRNA expression level of Htr‑1a decreased significantly on day 3 and 5 following surgery. The mRNA expression levels of tryptophan hydroxylase‑1 were unchanged in this short time period; however, the levels were increased gradually in the Leu treatment group. Therefore, Leu exhibited an apparent antifatigue effect on various 5‑hydroxytryptamine‑associated genes.