Figure 3.

Optical imaging of tumor-induced lymphangiogenesis with Cy5.5-LyP-1. At days 3, 7, 14 and 21 after 4T1 cell inoculation, tumor-bearing BALB/C mice (n = 5/group), under isoflurane anesthesia, were injected with Cy5.5-LyP-1 via the middle phalanges of both upper extremities. At 45 min after injection, in vivo fluorescence imaging of both tumor-draining LNs (a) and contralateral LNs (b) was performed with a Maestro II small-animal in vivo imaging system. The fluorescence images consisting of Cy5.5 and autofluorescence spectra were then unmixed based on their spectral patterns with the manufacturer’s software (Maestro software, CRI). The tumors are indicated by circles. (c and d) At 24 h post injection, the mice were killed and a dorsal skin flap was elevated to expose the brachial lymph nodes on both sides for a repeat of fluorescence imaging (c. tumor-draining LNs; d. contralateral LNs) (adapted from Zhang et al., 2012).