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Updated: Aug 7, 2026
Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology
Published on: December 7, 2011
Changes in Bone Mineral Density and Body Composition in Burn and Hindlimb Unloaded Rats
Juquan Song1, Gábor Törö1, Amina El Ayadi1
1Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555, United States.
Introduction:
Prolonged immobilization worsens the patient's recovery following severe burn injury and results in a prolonged hospitalization. This study aims to assess the alterations in bone mineral density and body composition in a pre-clinical model of cutaneous burn combined with immobilization.
Methods:
Adult male rats (n = 24) received scald burn of ∼40% total body surface area (TBSA) (B). After burn, 16 rats had their hindlimbs suspended (H) for either 3 days (BH3) or 14 days (BH14), whereas 8 rats underwent the burn procedure without suspension (B). Additional 8 rats without burn and hindlimb suspended were paired-housed and served as baseline controls (S). All rats were euthanized 21 days after burn for assessment using a high-resolution DEXA.
Results:
We found that ratios of rat whole body mass, normalized to pre-burn mass, were significantly decreased over time in all burned rats (B: 0.9072 ± 0.0517; BH3: 0.8997 ± 0.0145; BH14: 0.8618 ± 0.0666) when compared to the control (1.1542 ± 0.0206) (P < .05). The same significant reductions were observed in lean mass, bone mineral content (BMC), and fat content (P < .05). To determine whether the DEXA measurement of body parts correlates with whole-body measurement, we performed DEXA of the isolated left hindlimb dissected at the hip joint. We found the ratios of isolated hindlimb tissue mass significantly decreased in all burned rats (B: 0.0552 ± 0.0018; BH3: 0.499 ± 0.0050; BH14: 0.0459 ± 0.0033) when compared to the control (0.0738 ± 0.0046) (P < .05). In addition, there was a significant decrease in hindlimb tissue mass in burned animals suspended for 14 days compared to their burned nonsuspended counterparts (P < .05). The ratios of lean mass (0.0362 ± 0.0031) in the isolated hindlimb also significantly decreased in BH14 group compared to B group (0.0591 ± 0.0034) (P < .05).
Conclusion:
DEXA scanning of the whole body revealed a cachectic state in burned rats. The whole-body DEXA results were concordant with those obtained from the corresponding isolated hindlimbs. The isolated hindlimbs showed a further decrease in lean mass in burned rats following 14 days of immobilization. We conclude that 14-day immobilization exacerbates the cachectic state in severely burned rats. This preclinical model may be used to develop and test effective therapeutic countermeasures.
