An Experimental Study of the Effects of Cis-dichlorodiammineplatinum(II) and Irradiation on the Rat Livers

Cis-DDP has been used as a radiosensitizer in combination treatment modality far malignanttumors, of which mechanism is uncertain. The efects of combined Cis-DDP and irradiationon number of tumors have been studied in vitro and in vivo. The effects of combined Cis-DDP and irradiation on the liver are important because the liver is a radiosensitive organand frequently exposed to irradiation during treatment for intra-abdominal malignancies. Butthe studies of combined Cis-DDP and irradiation on the liver have not been reported.

So, this study was peformed to see the effect of Cis-DDP in combination with radiationon the liver. Total 66 Sprague-Dawley rats were divided into 5 groups; control, Cis-DDP(2.5mg/kg) administration, radiation(6, 8, lOGy, respectively), and combined Cis-DDP and radia-tion. which consisted of pre- and post-administration of Cis-DDP. Light and electron microscopic examination was performed 30 days after each experiments.

Cis-DDP administration induced mild congestion and focal hemorrhage in hepatic lobuleswith focal necrosis and degeneration of hepatocytes. Electron microscopic examination showedirregular cytoplasmic organelles and chromatin clumping in hepatocytes. In radiation treatmentgroup. hemorrhage of hepatic lobules, necrosis and degeneration of hepatocytes, edema andinflammation in portal tracts were aggravated with increased dosage of radiation. Hepatic lobulardisarray and inflammatory cell infiltration in portal tracts were noted from 8 Gy radiation.Vacuoles and electron dense bodies as well as swollen mitochondria in hepatocytes were frequently noted on electron microscopic examination. With combined treatment all He light andelectron microscopic changes were more severe than radiation alone regardless of sequenceof Cis-DDP administration and lobular disarray and inflammation in portal tracts were startedto note with 6 Gy radiation. When the hepatic lobular disarray and inflammation in portaltracts were used as end-points. the enhancement ratio of Cis-DDP was 1.3 in normal rat livers.