Chitosan-Based Hydrogel Microparticles for Treatment of Carcinoma in a Rabbit VX2 Liver Tumor Model

Purpose: To investigate potential of chitosan hydrogel microparticles (CHI) for treatment of VX2 carcinoma. Materials and Methods: Two weeks after liver VX2 implantation, contrast-enhanced computerized tomographic scanning was conducted. Rabbits (n = 2) with successful tumor growth were treated with different sizes of ^99mTc-labeled CHI (60–80 μm and 100–120 μm) via intra-arterial hepatic catheterization. Liver distribution of ^99mTc-labeled CHI was determined by means of autoradiography, a radiation-based photographic technique. In the next part of this study, therapeutic effectiveness was examined with the use of CHI with the size range of 60–80 μm (n = 11). Tumor growth response and levels of blood liver enzymes were studied at baseline and 1 and 2 weeks after CHI treatment. Results: Successful tumor growth was confirmed in all rabbits (24/24). Intrahepatic CHI with the size range of 60–80 μm resulted in liver localization in more close proximity to tumor nodule versus 100–120 μm. Baseline tumor volume was 1,909 ± 575 mm³ in animals receiving CHI versus 1,831 ± 249 mm³ in control animals (P =.342). In control animals, tumor volume markedly increased by 1,544 ± 512% at 2 weeks after sham operation versus baseline. In animals receiving CHI, tumor volume remained relatively unchanged (54 ± 6% increase; P =.007 vs control). Levels of blood aspartate transaminase (AST) and alanine transaminase (ALT) in animals receiving CHI increased 1 week after treatment (P =.032 vs control for AST; P =.000 vs control for ALT), but returned to control levels at 2 weeks. Conclusions: CHI embolization suppressed tumor growth without appreciable damages in liver function.