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Hypoxia-induced megaloblastosis in vitamin B12-deficient rats

Published online by Cambridge University Press:  01 August 2008

Shuhei Ebara ,
Satoko Adachi ,
Shigeo Takenaka ,
Toshiki Enomoto ,
Fumio Watanabe ,
Ryoichi Yamaji ,
Hiroshi Inui  and
Yoshihisa Nakano
Shuhei Ebara
Affiliation:
Department of Applied Biological Chemistry, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
Satoko Adachi
Affiliation:
Department of Applied Biological Chemistry, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
Shigeo Takenaka
Affiliation:
Department of Veterinary Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
Toshiki Enomoto
Affiliation:
Department of Food Science, Ishikawa Agricultural College, Nonoichi, Ishikawa 921-8836, Japan
Fumio Watanabe
Affiliation:
Department of Food and Nutrition, Kochi Women's University, Kochi 780-8515, Japan
Ryoichi Yamaji
Affiliation:
Department of Applied Biological Chemistry, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
Hiroshi Inui*
Affiliation:
Department of Applied Biological Chemistry, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
Yoshihisa Nakano
Affiliation:
Department of Applied Biological Chemistry, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
*
*Corresponding Author:Dr Hiroshi Inui, fax +81 72 254 9937, email inui@server.biochem.osakafu-u.ac.jp
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Abstract

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In rats, in contrast with human subjects who develop megaloblastic anaemia due to vitamin B12 deficiency, haematological abnormalities with anaemia were not observed under normoxic conditions even though plasma vitamin B12 concentration was reduced to <15 % of a normal concentration by depleting dietary vitamin B12. To elucidate whether erythropoiesis was affected by vitamin B12 deficiency in rats, these vitamin B12-deficient rats were exposed to hypoxia (10·5 % O2) to stimulate erythropoiesis. In the vitamin B12-sufficient control rats, erythrocyte count was significantly (P<0·05) increased 1 week after starting the hypoxic exposure. However, the hypoxia-induced erythropoiesis was affected by vitamin B12 deficiency, and no significant increase in the erythrocyte count was observed even after 6-week exposure to hypoxia in the vitamin B12-deficient rats. In the vitamin B12-deficient rats in hypoxia, erythrocytes became abnormally enlarged, and haemoglobin concentration in peripheral blood was increased in proportion to the increase of mean corpuscular volume. However, the level of the increase in the haemoglobin concentration was significantly (P<0·05) lower in the vitamin B12-deficient rats compared with that in the -sufficient controls. In addition, in the vitamin B12-deficient rats, in contrast to the -sufficient rats, serum erythropoietin concentration was not normalized even after 6-week exposure to hypoxia. These results indicate that a megaloblastic anaemia-like symptom is induced when the vitamin B12-deficient rats are exposed to hypoxia.

Keywords

Hypoxia-induced erythropoiesisMegaloblastic anaemiaErythropoietinVitamin B12-deficient rats
Type
Short communication
Information
British Journal of Nutrition , Volume 89 , Issue 4 , April 2003 , pp. 441 - 444
Copyright
Copyright © The Nutrition Society 2003

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