Vascular and stromal changes in irradiated and recovering rat thymus

Y. Wang1, N. Tokuda1, M. Tamechika1, N. Hashimoto1, M. Yamauchi2, H. Kawamura2, T. Irifune1, M. Choi4, A. Awaya3, T. Sawada1 and T. Fukumoto1

Departments of 1Anatomy and 2Urology, Yamaguchi University School of Medicine, 3Mitsui Pharmaceuticals, Inc. and 4Department of Anatomy, Won Kwang University Medical School, Republic of Korea

Offprint requests to: Yu-Hsueh Wang, First Department of Anatomy, Yamaguchi University School of Medicine, 1144 Kogushi, Ube 755-8505, Japan. Fax: +81-836-22-2203. e-mail: wang@po.cc.yamaguchi-u.ac.jp

Summary. To analyze the mechanisms responsible for thymocyte proliferation, maturation and migration in the thymus, the rat thymus just after, and recovering from irradiation was studied morphologically. The vascular structures of the rat thymus after a radiation dose of 6 Gy were found to be destroyed on day 3, but had recovered to almost normal by day 7, suggesting that the abrupt recovery of thymus structure after irradiation was due primarily to this change in vascular structure. Furthermore, the epithelial tissues in the thymic cortex appeared to contribute to this abrupt proliferation, and possibly to the abrupt maturation of thymocytes, while medullary epithelial tissues remained sparse and appeared inactive for a relatively long period. These findings are considered important for understanding the interrelationship between thymic epithelial cells and thymocytes with respect to thymocyte proliferation, maturation and migration. Histol. Histopasthol. 14, 791-796 (1999)

Key words: Thymus, Irradiation, Proliferation, Vascular structure, Reticular epithelial cells

DOI: 10.14670/HH-14.791