Near-infrared Fluorescent Imaging In Vivo Applied For Tongue Squamous Cell Carcinoma Imaging And Sentinel Lymph Node Mapping

Oral squamous cell carcinoma (OSCC) is a commonly malignant tumor in the head and neck area. The tongue is the most common site involved, and this incidence has retained the first in OSCC for many years. Tongue cancer is more likely to occurring metastasis in cervical lymph node at early stage, and causes severe malformation or malfunction and even then threatening patient's life. Accurate and early diagnosis play a key role in improving survival rate and quality for patients with tongue squamous cell carcinoma whilst nodal metastasis.Objectives:To explore near-infrared fluorescent imaging in vivo using quantum dots Qdot800 and Alexa680 dye labeling Nimotuzumab for tongue squamous cell carcinoma diagnosis, location and sentinel lymph node (SLN) mapping. Material and methods:Near-infrared fluorescent quantum dots Qdot800 and Alexa680 dye were respectively conjugated with Nimotuzumab. Subsequently, the probes were used to detect fixed or live human tongue squamous cell carcinoma cell line Tcca8113. After Tcca8113 subcutaneous xenografts grown in, the nude mice were injected intravenously with one of the conjugates followed by fluorescent imaging using small animal imaging system. The images of targeting tumor in vivo were required and analyzed. Furthermore, Qdot800 or Alexa680 dye was injected respectively in nude mice or rabbit's tongue. The fluorescent images were required and analyzed for evaluating SLN mapping.Results:Near-infrared fluorescent quantum dots Qdot800 and Alexa680 dye were successfully conjugated with Nimotuzumab. The conjugates were able to specifically and efficiently recognize fixed and live Tcca8113 with intense fluorescence. MTT test demonstrated both of the conjugates could evidently inhibit Tcca8113 growth. Although Nimotuzumab labeled with Qdot800 could not target the subcutaneous Tcca8113 xenografts grown in vivo, Nimotuzumab labeled with Alexa680 performed very well with bright fluorescence in contrast to surrounding normal tissue. Both of Qdot800 and Alexa680 successfully mapped SLN in vivo after locally injected in tongue. Meanwhile, Qdot800 showed more intense and lasting fluorescence as well as trapped in SLN for a long time.Conclusions:Near-infrared fluorescent Qdot800 and Alexa680 dye could be conjugated with Nimotuzumab. The fluorescent conjugates probes were able to target Tcca8113 cell in vitro. Qdot800 could not target Tcca8113 xenografts in vivo, but Alexa680 preformed excellently. Both of two materials could map SLN draining from tongue, while Qdot800 is more suitable for SLN mapping research.