Long-term bicycle riding ameliorates the depression of the patients undergoing hemodialysis by affecting the levels of interleukin-6 and interleukin-18

Abstract

Purpose: Hemodialysis patients with depression have a higher risk of death and hospitalization. Although there is pharmacological management for the depression of hemodialysis patients, the adverse effect of the drug limits the use. The nonpharmacological way, bicycle riding, may be an effective way for the therapy of the depression in hemodialysis patients. However, the underlying mechanism of this relationship is still not fully explained, while interleukin-6 (IL-6) and interleukin-18 (IL-18) are associated with depression and exercise. Thus, the effects of bicycle riding on the levels of the interleukin were explored.

Participants and methods: One hundred and eighty-nine patients with chronic hemodialysis were selected and randomly assigned to three groups of medicine (MG, received 20-mg escitalopram daily), medicine and aerobic exercise (MAG, received 20-mg escitalopram daily and bicycle riding six times weekly), and only aerobic exercise (AG, received 20-mg placebo daily and bicycle riding six times weekly). The whole experiment lasted for 18 weeks. The quality of life (36-Item Short Form Health Survey) and depression severity according to criteria in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition [DSM-IV] were measured before and at the end of this study. The serum levels of IL-6 and IL-18 were measured by an enzyme-linked immunosorbent assay kit.

Results: The quality of life was improved and depression severity was reduced significantly in the MAG and AG groups when compared with the MG group (P<0.05). Serum levels of IL-6 and IL-18 were the highest in the MG group, moderate in the MAG group and the lowest in AG group. On the other hand, the serum levels of IL-6 and IL-18 were closely associated with depression scores (P<0.05).

Conclusion: Aerobic exercise improves the quality of life and ameliorates the depression severity of the patients undergoing hemodialysis by affecting the levels of IL-6 and IL-18. Bicycle riding is a potential way for the depression therapy of the patients with chronic hemodialysis.

Keywords: aerobic exercise; depression; hemodialysis patients.

Figure 1

The flowchart of the present study. Note: All the experiments lasted for 18 weeks. Abbreviations: EEG, electroencephalography; MG, medicine group; MAG, medicine and aerobic exercise group; AG, aerobic exercise group.

Figure 2

The effects of serum IL-6 and IL-18 on the severity of depression. Notes: A total of 189 patients were selected after considering the inclusion and exclusion criteria and randomly assigned to the medicine group (MG, only received escitalopram 20 mg/day; 63 patients), medicine and aerobic exercise group (MAG; 63 patients), and aerobic exercise group (AG, placebo was used; 63 patients). (A) The effects of serum IL-6 on the severity of depression. (B) The effects of serum IL-18 on the severity of depression. ^*P<0.05 vs before therapy. Abbreviations: IL-6, interleukin-6; IL-18, interleukin-18.

Figure 3

The association between the scores of depression and serum levels of IL-6. Notes: A total of 189 patients were selected after considering the inclusion and exclusion criteria and randomly assigned to the medicine group (MG, only received escitalopram 20 mg/day; 63 patients), medicine and aerobic exercise group (MAG; 63 patients), and aerobic exercise group (AG, placebo was used; 63 patients). (A) The association between the scores of depression and serum levels of IL-6 in the MG group before therapy. (B) The association between the scores of depression and serum levels of IL-6 in the MG group after therapy. (C) The association between the scores of depression and serum levels of IL-6 in the AG group before therapy. (D) The association between the scores of depression and serum levels of IL-6 in the AG group after therapy. (E) The association between the scores of depression and serum levels of IL-6 in the MAG group before therapy. (F) The association between the scores of depression and serum levels of IL-6 in the MAG group after therapy. Abbreviation: IL-6, interleukin-6.

Figure 4

The association between the scores of depression and serum levels of IL-18. Notes: A total of 189 patients were selected after considering the inclusion and exclusion criteria and randomly assigned to the medicine group (MG, only received escitalopram 20 mg/day; 63 patients), medicine and aerobic exercise group (MAG; 63 patients), and aerobic exercise group (AG, placebo was used; 63 patients). (A) The association between the scores of depression and serum levels of IL-18 in the MG group before therapy. (B) The association between the scores of depression and serum levels of IL-18 in the MG group after therapy. (C) The association between the scores of depression and serum levels of IL-18 in the AG group before therapy. (D) The association between the scores of depression and serum levels of IL-18 in the AG group after therapy. (E) The association between the scores of depression and serum levels of IL-18 in the MAG group before therapy. (F) The association between the scores of depression and serum levels of IL-18 in the MAG group after therapy. Abbreviation: IL-18, interleukin-18.