A fluorescence imaging tool targeting burn wounds: research on the application of pH low insertion peptide / 中华核医学与分子影像杂志

ABSTRACT

Objective:pH low insertion peptide (pHLIP)-variant 7 (var7)-fluorescein isothiocyanate (FITC) was used to explore an accurate imaging tool that targeted burn wounds to better perform burn debridement.Methods:Twelve rat models of burn wound were established and pHLIP-var7-FITC with different concentrations (0.5, 1.5 and 2.0 mg/ml) were injected from the rat tail vein for in vivo fluorescence imaging. By determining the concentration of fluorescent conjugates to the burn wound, the scope of wound injury necrosis was judged by combining pathological sections, and its residue and toxicity in important organs such as heart, liver, kidneys, and brain were detected. The Kruskal-Wallis rank sum test, Bonferroni correction method and one-way analysis of variance were used for data analysis. Results:Within 24 h, the fluorescence photons per unit area of the burn wound in the group of 0.5 mg/ml, 1.5 mg/ml and 2.0 mg/ml were 1.49(1.31, 1.65), 2.46(1.88, 2.68), 2.77 (1.94, 3.10)×10 7 p·s -1·cm -2·Sr -1, with significant differences in the overall distribution of fluorescence photons ( H=73.55, P<0.001). The fluorescence intensity was stronger in the group with higher concentration, but with no significant difference in the number of fluorescence photons between the group of 1.5 mg/ml and 2.0 mg/ml ( P=0.263, Bonferroni correction method). At 14 time points (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 7.0, 8.0, 12, 24 h), there was no significant difference in the overall mean of fluorescence photons ( F=1.04, P=0.419), and the tissue with burn necrosis seen in tissue sections was highly consistent with the fluorescence imaging region. There was no obvious fluorescence residue in the heart, liver, kidney and brain sections. Conclusion:In superficial second-degree burn tissue, pHLIP-var7-FITC can accurately target and gather on the burn wound within 24 h, showing a clear boundary between burn tissue and normal tissue, which can assist clinical surgical debridement to determine the extent of injury.