Mammalian alpha-fetoprotein (AFP) is a single-chain glycoprotein and altered serum AFP levels have been observed concurrent with aberrant growth manifestations in some congenital defects and cancer. The gut development during late gestation and early neonatal period is accompanied by changes in the synthesis of AFP, and abundance declines significantly during gut development. In this case, AFP is considered as an important growth factor with a specific function in gastrointestinal development. The ontogeny of AFP gene expression has been examined in the fetal and adult mouse gastrointestinal tract to understand the basis of the ontogeny of AFP transcription in the gut and its regulatory elements. However, little is known about the expression pattern of AFP genes or its involvement during rat colon development.
A research team led by Dr Ying-Bin Ge from Nanjing Medical University, China addressed this question. Their study will be published on April 14, 2009 in the World Journal of Gastroenterology.
Colons from Sprague-Dawley rat fetuses, young and adult (8 wk old) animals were used in this study. Expression levels of AFP in colons of different development stage were detected by reverse transcriptase PCR (RT-PCR) and Western blotting. To identify the cell location of AFP in the developing rat colons, double-immunofluorescent staining was performed using antibodies to specific cell markers and AFP, respectively.
They found that the highest levels of AFP mRNA were detected in colons of rats at embryonic day 18.5 (e18.5). Compared to e18.5 d, the AFP expression was significantly decreased during rat development [85% for e20.5, P < 0.05, 58% for postnatal day 0.5 (P0.5), P < 0.05, 37% for P7, P < 0.05, 24% for P14, P < 0.05, and 11% for P21, P < 0.05] and undetected in adult rats. Only the 72-kDa isoform of AFP was detected by Western blotting, the expression pattern was similar to AFP mRNA and conformed to the results of mRNA expression. The AFP positive staining was identical to different distribution patterns in fetuses, young and adult animals and positive staining for both AFP and vimentin was overlapped in mesenchymal cells at each stage tested.
This study has for the first time demonstrated that AFP is localized in the mesenchyme of rat colon from the embryo to the weaning stage by immunofluorescence and presents 72-kDa isoform in the developing rat colons by Western blotting. The dynamic expression of AFP in the various developmental stages of the colon indicates that AFP might be involved in many aspects of colon development.
Liu XY, Dong D, Sun P, Du J, Gu L, Ge YB. Expression and location of alpha -fetoprotein during rat colon development. World J Gastroenterol 2009; 15(14): 1738-1743 http://www.wjgnet.com/1007-9327/15/1738.asp
Correspondence to: Ying-Bin Ge, MD, PhD, Department of Physiology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China. ybge@njmu.edu.cn
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World Journal of Gastroenterology (WJG), a leading international journal in gastroenterology and hepatology, has established a reputation for publishing first class research on esophageal cancer, gastric cancer, liver cancer, viral hepatitis, colorectal cancer, and H pylori infection and provides a forum for both clinicians and scientists. WJG has been indexed and abstracted in Current Contents/Clinical Medicine, Science Citation Index Expanded (also known as SciSearch) and Journal Citation Reports/Science Edition, Index Medicus, MEDLINE and PubMed, Chemical Abstracts, EMBASE/Excerpta Medica, Abstracts Journals, Nature Clinical Practice Gastroenterology and Hepatology, CAB Abstracts and Global Health. ISI JCR 2003-2000 IF: 3.318, 2.532, 1.445 and 0.993. WJG is a weekly journal published by WJG Press. The publication dates are the 7th, 14th, 21st, and 28th day of every month. WJG is supported by The National Natural Science Foundation of China, No. 30224801 and No. 30424812, and was founded with the name of China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.
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