Monitoring the Health Status of Mice with Bleomycin-induced Lung Injury by Using Body Condition Scoring

Area of Science:

• Animal models
• Pulmonary toxicology
• Fibrotic lung disease

Background:

• Humane endpoints are crucial for monitoring animal health during disease.
• Body condition scoring (BCS) assesses health in mouse studies, but its utility in bleomycin-induced lung injury is unknown.
• Body weight (BW) is a common endpoint, but lung changes can mask true physical condition.

Purpose of the Study:

• To evaluate the effectiveness of BCS in monitoring health status in a mouse model of bleomycin-induced lung injury.
• To determine if BCS can serve as an appropriate humane endpoint in this model.

Main Methods:

• Acute bleomycin (0.075 U) or saline was instilled into the lungs of male C57BL/6 mice via trachea.
• Body weight (BW), body condition score (BCS), and lung weight were measured.
• Soleus and visceral epididymal fat masses were assessed.
• Correlations between BW, BCS, lung weight, and fat mass were analyzed.

Main Results:

• Bleomycin instillation significantly increased lung weight and decreased BW and BCS compared to saline controls.
• Changes in BW and BCS were significantly correlated with increased lung weight.
• BCS changes correlated significantly with decreases in soleus and visceral epididymal fat mass.
• Adjusted BW (corrected for lung weight) showed unchanged correlation, indicating BW did not significantly mask decreases.

Conclusions:

• Body weight (BW) and body condition scoring (BCS) are significantly correlated with lung injury in the bleomycin-induced lung fibrosis model.
• BCS is a suitable alternative humane endpoint for monitoring health status in this mouse model.
• BCS reflects systemic loss of muscle and fat mass during lung injury.