Development of a novel rabbit auricle xenograft model of human PC3 prostate cancer.

Abstract

Background: Therapeutic management of prostate cancer remains challenging. Prostatic artery chemoembolization (PACE), an advanced minimally invasive technique derived from prostatic artery embolization (PAE), has shown promising potential in controling tumor growth and alleviating symptoms such as hematuria and lower urinary tract obstruction in prostate cancer, and has garnered widespread attention in recent research. However, preclinical progress is hindered by the limitations of existing animal models, and the development of a simple and reliable animal model to better understand the endovascular interventional treatment of prostate cancer is necessary.

Objectives: To develop and characterize a novel xenograft model of human prostate cancer in the rabbit auricle as a practical platform for experimental research on endovascular embolization techniques.

Materials and methods: Fresh human PC3 cell suspension (0.1 ml containing ~ 9 × 10⁶ cells) was injected subcutaneously into each auricle of 15 immunosuppressed New Zealand white rabbits. Tumor growth was measured periodically, and volume doubling time (VDT) was calculated. Digital subtraction angiography was performed via the central auricular artery when tumors were greater than 150 mm³. Subsequently, histopathological and immunohistochemical analyses were conducted. Repeated-measures ANOVA was used to assess the significance of differences in the VDT of auricle tumors within-rabbits and between rabbits.

Results: The model achieved a high tumor take-rate of 86% (26/30 auricles). Angiography revealed distinct tumor-feeding vessels and uniform ring-like staining. Histopathology confirmed invasive growth of poorly differentiated, atypical tumor cells with high mitotic activity and no obvious necrosis. Immunohistochemistry showed high Ki67 expression (82.43 ± 3.68)%, indicating active proliferation. During the exponential growth stage, the mean VDT was 6.4 ± 1.8 days. Repeated-measures ANOVA revealed significant variations in VDT among the rabbit subjects (P < 0.05); moreover, the VDT did not significantly differ between the left and right ears of each rabbit (P > 0.05), thereby reinforcing the consistency of the model employed.

Conclusions: The rabbit auricle PC3 xenograft model is a valuable preclinical platform. It effectively simulates human prostate cancer with high reproducibility and clear vasculature, providing a foundational tool for subsequent investigations into the efficacy of endovascular therapies, such as PAE and PACE.