Comparative Evaluation of the Biodegradability and Biocompatibility of Agarose Gel and Hyaluronic Acid Filler.

[BACKGROUND] The clinical success of soft tissue fillers hinges on their biodegradability and biocompatibility. While agarose gel, a clinically available filler, shows versatility across injection sites, its degradation behavior and tissue effects remain poorly understood.

[OBJECTIVE] This study aimed to compare the biodegradability and biocompatibility of agarose gel and hyaluronic acid fillers using a rat model.

[METHOD] Agarose gel and hyaluronic acid were subcutaneously injected into Sprague-Dawley rats' dorsal regions. MRI scans at 1, 3, 6, 9, and 12 months assessed filler volume and distribution. SEM examined morphology, in vitro tests measured water absorption, and histology at 12 months included HE staining and immunohistochemistry for collagen and macrophage markers.

[RESULT] Hyaluronic acid exhibited higher water absorption than agarose gel (p < 0.05). MRI revealed greater initial volume retention for hyaluronic acid (0.762 ml vs. 0.283 ml, p = 0.025), while agarose gel demonstrated a slower biodegradation rate during the first three months (86.24% vs. 61.88%, p = 0.004) and greater early-phase dispersion (109.89% vs. 65.24%, p = 0.020). At 12 months, no significant difference in final volume retention was observed. Both fillers showed good biocompatibility, with no signs of fibrosis or inflammation after one year.

[CONCLUSION] These findings from an animal study suggest agarose gel's potential as a safe and effective alternative for soft tissue augmentation.

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