Stress-protective effects of human lactoferrin in a rat model of experimental chronic stress

Background: Severe stress is associated with immune, neuroendocrine, cardiovascular, and other system dysfunctions and may cause various neurochemical and behavioral alterations. Stressful life events have been shown to play a role in the etiology of depression and anxiety. The search for therapeutic options in such disorders remains a relevant task of both fundamental and clinical medicine. This work investigates the stress-protective properties of molecular factors of innate immunity, specifically the iron-binding protein lactoferrin. Aim: The work aimed to examine the antistress effect of human lactoferrin on behavioral disturbances in laboratory animals (rats) induced by chronic stress. Methods: For stress induction, a rat model of chronic stress was used, involving daily forced swimming of laboratory animals in cold water. Locomotor activity, as well as emotional and exploratory behavior, were assessed. RESULTS: It was shown that this stress exposure does not alter locomotor activity in rats, but increases anxiety and reduces exploratory activity, resulting in a depression-like state. Daily oral administration of human lactoferrin at a dose of 200 μg/kg body weight reduced anxiety and restored exploratory activity. Conclusion: The findings indicate that rats subjected to chronic stress develop a depression-like state, which can be mitigated by oral administration of low doses of human lactoferrin. Thus, lactoferrin is more than just an endogenous antimicrobial and chelating compound. In addition to its anti-infective properties, lactoferrin is involved in a variety of other protective mechanisms, including its potential role as an endogenous antidepressant.