Study on the effects of focal injection of 32P-chromic phosphate colloid on pancreatic carcinoma (Pc-3) and its radioactivity in the lymph node

Objective: To study the anti-tumor effects and its mechanism of focal injection of 32P-colloid on nude mice bearing pancreatic carcinoma (Pc-3) and its radioactivities in the lymph node. Methods: Forty-eight tumor-bearing mice were randomly divided into 8 groups of 6 mice. Mice of group 1-6 (3.7, 7.4, 14.8, 18.5, 29.6 MBq injected group and 0 MBq as control) were sacrificed 14 d after administration. Group 7 and 8 (14.8 MBq and blank control) were remained alive for about 40 d with an average of 30 d. The levels of 32P in the tumor, rates of necrosed tumor cells, morphological changes and microvessel density (MVD) that was counted for the positive expression of CD34 protein were studied by microspectroscopy, electron microscopy and immuno-chemistry after injection of 32P-chromic phosphate colloid. The effects of 32P-colloid on biological behavior of groin lymph node (GLN) were dynamically observed. Results: 32P-colloid mainly accumulated in the tumor after intratumoral injection. The rate of necrosed tumor cells was 20%, 45%, 65%, 70%, 95% and 4% (F=4.14-105.36, P<0.01), respectively in group 1-6, and the MVD counts were 38.5±4.0, 28.0±2.9, 17.0±2.9, 8.8±1.5, 5.7±2.3 and 65.0±5.2 (t=11.9-26.1, P<0.01), respectively. The tumors of group 7 were reduced, shriveled, scabbed and desquamated at last. The swelling of GLNs in the 32P groups was milder and occurred later than that of the control group (6,8), and the radiodamaging of GLN was positively correlated with the dose administered. Although the tumors had integrated membrane but lymph node metastases were detected, and the tumor cells died degeneratively after radioactivated by 32P-colloid. The tissue returned to normal after 4 weeks. Conclusion: The anti-tumor effect of 32P-colloid intratumoral injection is significant, and it is a satisfying intervention approach to treat both pancreatic carcinoma and local lymph node metastasis