Morphological Features of Adult Rats of IS/Kyo and IS-Tlk/Kyo Strains with Lumbar and Caudal Vertebral
Anomalies |
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Authors: | Masao Takano Emi Ogawa Tsubasa Saitou Yuko Yamaguchi Yuzo Asano Tadao Serikawa Takashi Kuramoto |
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Institution: | 1) Gotemba Laboratory, Bozo Research Center Inc., 1284 Kamado, Gotemba-shi, Shizuoka 412-0039, Japan;2) Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Japan |
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Abstract: | IS-Tlk/Kyo, a mutant derived from IS/Kyo strain,
exhibits a kinked and/or short tail, in addition to the congenital lumbar vertebral
anomaly. Homozygotes of Tlk dominant gene are known to die during
embryonic development. We previously reported the morphological features of the skeleton
in IS/Kyo and IS-Tlk/Kyo fetuses and of the heart in
IS/Kyo fetuses 19]. This study was conducted to
clarify the morphological features of the skeleton in both adult rats and of the heart in
adult IS/Kyo rats. Ventricular septal defect (VSD) was observed in 3 out of 10 IS/Kyo
rats. Neither splitting of lumbar vertebra and supernumerary rib (in both strains) nor
fused or absent caudal cartilage (in IS-Tlk/Kyo strain) was detected in
adult rats. Fusion of lumbar vertebrae was observed in almost all specimens together with
lumbarization of sacral vertebrae in a few specimens in both adult rats as well as fusion
of sacral and caudal vertebrae only in adult IS-Tlk/Kyo rats. In
addition, a severe reduction in the ossified sacral and caudal vertebrae was noted in
adult IS-Tlk/Kyo rats (mean number: 20.6) and IS/Kyo
rats (31.8), and the difference was similar to that in the length of sacral and caudal
vertebrae. These results suggest that the Tlk gene may be involved in
both the congenital and acquired abnormal formation of the lower vertebral centra as well
as the persistent occurrence of VSD by the background gene in IS/Kyo strain. |
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Keywords: | IS rat lumbar vertebral anomalies sacral and caudal vertebrae Tlk gene ventricular septal defect |
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