Evaluating fatigue in lupus-prone mice: preliminary assessments

Area of Science:

• Neuroscience
• Immunology
• Behavioral Science

Background:

• Chronic fatigue affects numerous individuals with chronic diseases, yet its biological underpinnings and management strategies remain poorly understood.
• Systemic Lupus Erythematosus (SLE) frequently presents with fatigue, impacting over half of patients.

Purpose of the Study:

• To investigate and evaluate chronic fatigue in lupus-prone mice.
• To identify reliable behavioral indicators for assessing fatigue in a disease model.

Main Methods:

• Lupus-prone (MRL/lpr) and control (MLR⁺/(+)) mice were tested at 12, 16, and 20 weeks of age.
• Behavioral tests included forced swim, post-swim grooming, running wheel activity, and sucrose consumption.
• An operant conditioning task was administered to a subset of mice to assess motivation and muscle function.

Main Results:

• MRL/lpr mice exhibited lupus symptoms like lymphadenopathy and proteinuria.
• Lupus mice displayed increased floating time in the forced swim test and reduced running wheel distance.
• No significant differences were observed in grooming or operant conditioning, suggesting fatigue, not weakness or lack of motivation, drove behavioral changes.

Conclusions:

• Lupus-prone mice demonstrate behavioral characteristics indicative of chronic fatigue.
• Running wheel activity and forced swim test performance serve as valid measures for evaluating fatigue.
• Further research is needed to differentiate fatigue from depressive-like states in these behavioral outcomes.