Inhibition of growth in a rabbit VX2 thigh tumor model with intraarterial infusion of carbon dioxide-saturated solution

Abstract

Purpose: To evaluate the efficacy of intraarterial infusion of CO2-saturated solution in rabbit VX2 thigh tumors.

Materials and methods: Fourteen Japanese white rabbits had VX2 tumors implanted in the right femoral muscle 3 weeks before intraarterial infusion. Rabbits were divided into control and CO2 groups (n = 7 each). Fifty milliliters of solution (saline solution and CO2-saturated solution for the control and CO2 groups, respectively) was administered via a 24-gauge catheter in the ipsilateral iliac artery close to the feeding artery of the VX2 tumor. All rabbits were killed for tumor harvest on day 3 after the procedure. Tumor volume was evaluated with in vivo direct caliper measurement and contrast-enhanced computed tomography (CT). Tumor apoptotic changes were examined by DNA fragmentation assay and immunoblot analysis. The tumor growth ratio and apoptotic cell rate were analyzed.

Results: Body weight was equally increased in both groups, but the mean tumor growth ratio was significantly decreased in the CO2 group compared with the control group (-9.5% ± 7.9 vs 27.2% ± 6.6 and 4.1% ± 4.4 vs 35.7% ± 4.5 measured by calipers and contrast-enhanced CT, respectively; P < .01). Apoptotic activity in the CO2 group was higher than in the control group (number of apoptotic cells per area, 215.0 ± 58.7 vs 21.8 ± 5.4; adjusted relative density of cleaved caspase-3, 0.23 ± 0.07 vs 0.04 ± 0.01; P < .01).

Conclusions: Intraarterial infusion of CO2-saturated solution inhibits rabbit VX2 thigh tumor growth by activation of apoptotic cell death through cleaved caspase-3 upregulation.