Optimization and Standardization of the Immunodeficient Mouse Model for Assessing Fat Grafting Outcomes

Area of Science:

• Regenerative Medicine
• Tissue Engineering
• Plastic Surgery

Background:

• Variability in animal models hinders standardization of fat grafting research.
• Immunocompromised mouse models are frequently used but their predictive value requires assessment.

Purpose of the Study:

• To evaluate the predictive accuracy of the immunocompromised mouse model for fat grafting outcomes.
• To standardize and optimize fat grafting experiments using reliable animal models.

Main Methods:

• Human lipoaspirate was injected into nude mice at various volumes and time points.
• Volume retention and histological scores were compared between viable and nonviable fat grafts.
• Interanimal reproducibility was assessed using a consistent hydrogel implant.

Main Results:

• Graft volume significantly impacted adipose resorption at 6 and 12 weeks.
• Large (1 ml) grafts developed unresorbed oil cysts, confounding volume retention data.
• Histological viability of 0.3 ml grafts correlated well with retention; interanimal variability was 8.44%.

Conclusions:

• Small (0.3 ml) fat grafts in immunocompromised mice show correlation between viability and retention.
• Large grafts (1.0 ml) yielded confounded volume measurements due to unresorbed oil cysts.
• Delayed immune reactions may affect fat graft outcomes in this model at 18 weeks.