Effect of the Paclitaxel and Radiation on the Gastric Mucosa of the Rat

Lee, Kyung Ja; Koo, Heasoo

Abstract

PURPOSE: Paclitaxel is a chemotherapeutic agent with potent microtubule stabilizing activity that arrests cells in G2-M phase. Because G2 and M are the most radiosensitive phase of the cell cycle, paclitaxel has potential role as a cell-cycle specific radiosensitizer. This study was performed to see the effects of paclitaxel on the radiation-induced damage of gastric mucosa of the rat.
MATERIALS AND METHODS
The rats were divided into the three groups i.e., paclitaxel alone group, radiation alone group and, a combination of paclitaxel and radiation in combined group. A single intraperitoneal infusion of paclitaxel (10 mg/kg) was done in paclitaxel alone group. In radiation alone group, a single fraction of irradiation (8 Gy, x-ray) to the whole abdomen and, a combination of a single fraction of irradiation (8 Gy, x-ray) to the whole abdomen was given 24 hrs after paclitaxel infusion in combined group of paclitaxel and radiation. The incidence of mitosis and apoptosis as well as histologic changes of the gastric mucosa were evaluated at 6 hrs, 24 hrs, 3 days and 5 days after treatment.
RESULTS
The number of the mitosis was not increased by paclitaxel infusion. The incidence of the apoptosis was similar from 6 hrs to 3 days after paclitaxel infusion and was decreased at 5 days. Paclitaxel induced minimal glandular dilatation and cellular atypia of gastric mucosa at 24 hrs and 3 days. In irradiation group, the incidence of apoptosis was 6.0% in 6 hrs and 1.25% in 24 hrs after irradiation and minimal glandular dilatation and cellular atypia were noted throughout the experimental period. The incidence of apoptosis in the combined group of paclitaxel and irradiation (4.5%) was significantly higher than irradiation alone group (1.25%) at 3 days (p<0.05).
CONCLUSION
Paclitaxel had no effect on mitotic arrest in gastric mucosa of the rat. Increased number of apoptosis in combined paclitaxel and irradiation group suggested the additive effects of paclitaxel on irradiation.