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Updated: Jul 26, 2025
Assessment of Viability of Human Fat Injection into Nude Mice with Micro-Computed Tomography
Published on: January 7, 2015
Particles of Different Sizes Affect the Retention Pattern of the Fat Grafts in a Mouse Model
Ziang Zhang1, Zijin Qin1, Jiezhang Tang1
1Department of Plastic and Reconstructive Surgery, Xijing Hospital, Fourth Military Medical University, No. 127 Changle West Road, Xi'an, Shaanxi Province, China.
Background:
Autologous fat grafting is an effective form of soft tissue regeneration. However, the optimal fat particle size and graft retention pattern need more research.
Methods:
The mouse inguinal fat pad was harvested and cut into fat particles of different diameters: ≥ 5 mm, 3-4 mm, 2-3 mm, 1-2 mm and 1 mm (micro-fat). A volume of 0.2 ml fat was transplanted into another mouse dorsum. Volume and retention rate were measured at 1, 4, 8 and 12 weeks. Histology analysis was performed. Immunofluorescence staining was used to evaluate M1 and M2 macrophage infiltration and graft angiogenesis.
Results:
Fat retention was highest in the "> 5 mm" group and lowest in the "micro-fat" group. Large vacuoles were more common in larger-diametered fat particles. There was less collagen accumulation in the well-vascularized connective tissue in the "1-2 mm" group. The infiltrated nucleated cells peak at week 4 in groups of fat particles under 3 mm and at week 8 in in groups with fat particles above 3 mm. The number of M1 macrophages peaked at week 1 and then declined in all groups except for the "5 mm" group. The number of M2 macrophages peaked at week 4 and gradually decreased through 12 weeks in the groups below 3 mm, but increased through 12 weeks in the groups above 3 mm. Vascular intensity was similar to M2 macrophage prevalence.
Conclusions:
Fat particles of different sizes may posses different retention patterns. Larger grafts have higher retention rate but worse quality. Meanwhile, smaller grafts have better quality with lower retention rate.
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