Chromosome Aberrations in Malformed Rat Fetuses Induced with Trypan Blue

Lee, Moo Sang; Wang, Chong Soon

Abstract

It is now well known that several human congenital syndromes are accompanied by chromosomal aberrations. Chromosomal aberrations can also be induced by several teratogenic agents in various species of animals when exposed to these agents at certain embryonic development (Installs et al.. 1963 ; Soukup et al., 1967 ; Joneja and Ungthavorn. 1968 ; Roux et al., 1970). A hereditary component in the etiology of urinary tract malformations has been reported in man and animals (Bagg. 1929 ; Deringer and Heston, 1956 ; Monie et al., 1957 ; Roux and Dupuis. 1961 ; Fujikura, 1969). The extent of hereditary influence. however, is difficult to in man, and even the major cause of congenital hydronephrosis is still unknown. The main purposes of this investigation is to determine whether trypan blue which induces congenital anomaly of urinary tract in rat embryos would also induce Chromosomal aberrations in the embryos and the mothers. Sprague-Dawley strain healthy female rats were examined for the spermatozoa in the vaginal smears everyday. Trypan blue solution 1.5% was injected subcutaneously with various doses at different developmental stages of rat embryos. For embryonic studies, the animals were killed on the 20th day of gestation. The total implantations, resorption rates and sex ratios were examined. Under the stereomicroscope. anomalies such as hydronephrosis, renal hypoplasia and agenesis, and anomaly of location. position and rotation of the kidney were examined through the micro-dissection method and confirmed histologically. For Chromosomal studies, the bone marrow cells of mothers and the liver cells of fetuses were examined cytogenetically by means of the culture method of Roux et al. (1970). From the data obtained, results were as follows; 1. Resorption of fetuses, growth retarding effects and chromosomal aberrations of fetuses were increased following the increased doses of trypan blue, but time of injection was more important in production of the malformations. 2. Following the increased doses of trypan blue and early injection, male fetuses were more produced. So it seemed that female fetuses were easily resorpted. 3. The timing of injection with trypan blue exerted greater influence upon the inducement of hydronephrosis than the doses of the chemical, but in cases of other malformations, vice versa. 4. In mothers chromosomal aberrations were related with the doses of the teratogen, but in fetuses, with the timing of injection. 5. So far as trypan blue is concerned, it is probable that there is a close relationship between chromosomal aberration and teratogenecity.