Development and Evaluation of a New In Vivo Volume Measuring System in Mouse Tail Lymphedema Model

Secondary lymphedema is a common complication of parasitization and breast or gynecologic cancer therapy; however, options for the treatment of lymphedema are ineffective and limited. A mouse tail model is one of the most successful animal models for a lymphatic study. Lymphedema of the mouse tail is characterized by increases in the volume of the extremity caused by accumulation of tissue fluid, proliferation of fibroblasts and adipocytes, and excessive production of collagen. However, the study of lymphedema using mouse has been plagued with difficulty in directly assessing physiologic changes owing to limitations in the measurement of the mouse tail volume. Furthermore, the mouse tail volume cannot be obtained using the general in vivo measurement method such as volumetric water displacement. Lymphatic researchers have used the truncated cone formula to approximate the volume as used in the numerical approximation of a cylindrical figure. Although this formula is simple and easy to use, it has difficulties of repeatability and accuracy because the measurement procedure is highly subjective and the accuracy depends on the number of divided segments on the tail. In this article, two novel volumetric measurement methods for the mouse tail model were introduced. The methods were evaluated and compared using three mice with surgically created lymphedema on the tails. The two continuous measuring methods showed a possibility to improve the conventional method by continuous measurement using visual and physical detecting methods. The proposed methods facilitate the extraction of longitudinal section-specific information, which can be an important clue in a lymphatic study.