Effect of combined radiation-burn injury on cell number, morphology and IL-12 gene expression of peritoneal macrophages in mice

Objective: To investigate the effect of combined radiation-burn injury on cell number, morphology and IL-12 gene expression of peritoneal macrophages (pMΦs) in mice. Methods: At different time points after combined radiation-burn injury (CRBI) or radiation injury (RI) pMΦs of mice were purified, counted and observed under light microscope, and the IL-12 transcriptive level was measured with RT-PCR. Results: 1) Compared with RI group, pMΦs decreased more quickly and seriously at early stage, but recovered better at late stage in CRBI group; 2) Compared with the irradiation group, there was more necrocytosis in early stage in the CRBI group, but pMΦs in the CRBI group looked closer to normal; 3) IL-12 p35 transcription levels were suppressed while that of p40 elevated in both CRBI and RI groups. However the transcriptive levels of p35 and p40 was higher in the CRBI group those in the RI group. Conclusion: The effect of combined radiation-burn injury on cell number, morphology and IL-12 gene expression of pMΦs are characterized as 'worsening at early stage, lightening at late stage', implying the significance of early treatment of CRBI