Autoradiographische Untersuchungen über die Zellkinetik der Kryptenepithelien im Jejunum von Ratten nach experimenteller Blockade des Ductus thoracicus in Höhe des linken Venenwinkels

Abstract These investigations were carried out on rats with a thoracic duct blockade at the base of the neck. In these animals we determined the labeling index, the mitotic index and the number of cells per villus and per crypt. Growth fraction (G. F.), the percentage of labelled mitoses (P.L.M.) curves, and the results of the 3 H- 14 C-TdR double labeling method were obtained from rats on the 7 th postoperative day. Availability was determined by counting silver grains above the nuclei of epithelial crypt cells 20, 40, 60, and 120 min. after a single injection of 3 H-TdR. The availability of 3 H-TdR is given by the time at which the curves reach a saturation level. In these experiments we found a depresssion in the 3 H-TdR labeling index as well as in the mitotic index and in the number of epithelial cells per crypt and per villus. DNA synthesis time (Ts), generation (cycle) time (Tc), and G1 time (T G1 ) were increased whereas G2 plus mitotic time (T G2 + T M ) and the availability remained unchanged. The G.F. decreased from 59% in the controls to 45% in the thoracic duct operated animals. The depression of the 3 H-TdR index and the mitotic index was not due to an increase in Ts, T G1 , and Tc, but to a decrease in the G.F. As a consequence of this decrease in the G.F. and the increase in cell cycle times, we found a reduction of the number of epithelial cells per crypt and per villus. After 2–3 weeks all parameters had returned to normal. These experiments therefore further strengthen our previous studies on liver and kidney of rats after thoracic duct blockade.