Alleviative effects of foraging exercise on depressive-like behaviors in chronic mild stress-induced ischemic rat model

ABSTRACT

Background

Poststroke depression (PSD) is a common complication that seriously affects the functional recovery and prognosis of an individual. As some patients with PSD fail to respond to drug therapy, it is urgent to find a viable alternative treatment.

Methods

An active exercise program known as foraging exercise (FE), using food as bait, was designed. First, focal ischemia and chronic unpredictable mild stress (CUMS) were used to establish a PSD model in rats. FE was then performed for 4 weeks. Body weight and behavioral assessments were conducted at the end of the 4^th and 8^th weeks.

Results

After 8 weeks, the results revealed that, compared with the PSD group, the behavioral scores of the rats in the PSD/FE group were significantly improved, the expression of Iba-1 in the affected frontal lobe and striatum was decreased, and serum levels of IL-6 and the IL-6/IL-10 ratio were downregulated. However, the ratio of residual brain volume in rats that had experienced CUMS was significantly less than that in the stroke group.

Conclusion

FE can alleviate the behavioral scores of PSD rats, and its mechanism may be related to a modulation of the immune-inflammation response of microglia. Furthermore, chronic, persistent stress may increase the volume of cerebral infarction after stroke.

KEYWORDS:

• Chronic stress
• cerebral infarction volume
• foraging exercise
• inflammatory factors
• microglia
• poststroke depression

Abbreviation

CUMS, chronic unpredictable mild stress; FE, foraging exercise; I/R, ischemia-reperfusion; Iba-1, ionized calcium binding adaptor molecule 1; MCAO, middle cerebral artery occlusion; NSFT, novelty suppressed feeding test; OFT, open field test; PSD, poststroke depression; r-TMS, repetitive transcranial magnetic stimulation; SD, standard deviation; SIT, social interaction test; SP, sucrose preference; SPT, sucrose preference test; tDCS, transcranial direct current stimulation; VRB, volume of residual brain.

Acknowledgments

The authors would like to thank Professor Qing Wang (Zhujiang Hospital, Southern Medical University) for his providing of Iba-1 antibody.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website

Additional information

Funding

This work was supported by the Scientific research project of Hunan Health Committee [20200176]; Scientific research project of Hunan Education Department [20C1172]; Natural Science Foundation of Hunan Province [2018JJ6104].