Multimodality imaging of P4 MSCs in nude mice.

<p>(A) Bioluminescence imaging of nude mice injected with P4 MSCs cells isolated from the tri-fusion transgenic mice at day 0. 1x10³ (A.1), 5x10³ (A.2), 1x10⁴ (A.3), 5x10⁴ (A.4), 1x10⁵(A.5), 2.5x10⁵ (A.6), 5x10⁵ (A.7), 1x10⁶ (A.8), 2x10⁶ (A.9), and 4x10⁶ (A.10). MSCs were injected into nude mice, and then fluorescence imaging was performed immediately. One hour later, the same mice were imaged for bioluminescence signal following intraperitoneal injection of D-Luciferin. 1X10³ (A.1) cells are detectable by bioluminescence imaging. (B) Correlation of cell numbers (x-axis) with bioluminescence signal. Results demonstrated linear relationship between bioluminescence signal and cell number, with R² values of 0.93. (C) Micro-PET imaging of the same nude mice. Following a bioluminescence scan, the mouse was imaged in microPET using FHBG. The PET signal was found in the mouse injected with 2.5x10⁵ (C.6) or more MSCs. (D) Correlation of cell numbers (x-axis) with micro-PET signal. Results demonstrated linear relationship, with R² values of 0.94. (E) Correlation of fluc and ttk gene expression. Results demonstrated linear relationship, with R² values of 0.97. p/s = photons per second; % ID/g = percentage of injection dose per gram.