Argon-helium cryosurgery for treatment of C6 gliomas in rats and its effect on cellular immunity

Argon-helium cryosurgery has shown encouraging therapeutic effects on some solid tumors, but its application in the treatment of gliomas remains poorly documented. To explore the cell apoptosis at the glioma foci and the cellullar immunity changes following argon-helium cryosurgery, we established Wistar rat models bearing subcutaneous C6 glioma and divided the rats into the normal control (20 rats), sham-operated (32 rats), surgical resection (20 rats), and cryosurgery (32 rats) groups with corresponding treatments. The postoperative changes in the findings by magnetic resonance imaging (MRI) and tumor cell morphology were observed, and the cell apoptosis at the tumor foci was assessed with TUNEL assay. Flow cytometry was performed for analysis of the T lymphocyte subset changes following the cryosurgery. The results showed that cryosurgery induced not only destruction of the tumor cells but also cell apoptosis around the cryablation foci. Compared with surgical resction that caused significant reduction in CD3+ and CD4+ cell percentages, cryosurgery resulted in significantly increased percentages of CD3+ and CD4+ cells (P<0.05) with a relative increase of the CD4+/CD8+ cell ratio 14 days after the operation. These results demonstrate that in addition to tumor cell destruction, cryosurgy also results in enhanced cellular immunity and antitumor immune response of the C6 glioma-bearing rats, suggesting the great potential of argon-helium cryosurgery in clinical management of gliomas.