The enhancing role of vitamin A deficiency on chemically induced nephroblastoma in rats

How Dietary Deficiency Studies Have Illuminated the Many Roles of Vitamin A During Development and Postnatal Life

Vitamin A deficiency studies have been carried out since the early 1900s. Initially, these studies led to the identification of fat soluble A as a unique and essential component of the diet of rodents, birds, and humans. Continuing work established that vitamin A deficiency produces biochemical and physiological dysfunction in almost every vertebrate organ system from conception to death. This chapter begins with a review of representative historical and current studies that used the nutritional vitamin A deficiency research model to gain an understanding of the many roles vitamin A plays in prenatal and postnatal development and well-being. This is followed by a discussion of recent studies that show specific effects of vitamin A deficiency on prenatal development and postnatal maintenance of the olfactory epithelium, brain, and heart. Vitamin A deficiency studies have helped define the necessity of vitamin A for the health of all vertebrates, including farm animals, but the breadth of deficient states and their individual effects on health have not been fully determined. Future work is needed to develop tools to assess the complete vitamin A status of an organism and to define the levels of vitamin A that optimally support molecular and systems level processes during all ages and stages of life.

Vitamin A Inhibits Development of Dextran Sulfate Sodium-Induced Colitis and Colon Cancer in a Mouse Model

Vitamin A is essential to mucosal immunity and cell differentiation. The fact that lack of it might involve chronic inflammation and increased risk of cancer has been reported. Little is known about the mechanism of vitamin A deficiency in the development of colitis and its influence on development of colorectal cancer. To determine the influence of vitamin A deficiency on colitis and colorectal cancer development, an experimental study using a colitis mouse model was performed. Dextran sulfate sodium (DSS) colitis was induced in vitamin A-deficient and vitamin A-supplemented mice. Further, colorectal carcinoma was induced by a combination of azoxymethane preinjection and DSS colitis. Results were compared between the two groups mainly by immunohistochemical analysis. Colitis was more severe and recovery from colitis was slower in vitamin A-deficient mice than in vitamin A-supplemented mice. Compared with vitamin A-supplemented mice, vitamin A-deficient mice had decreases in colonic subepithelial myofibroblasts and the ratio of mucosal IgA(+)/IgG(+) cells, increases in CD11c(+) dendritic cells, and a higher rate of development of colorectal carcinoma with colitis following azoxymethane. Vitamin A lipid droplets in subepithelial myofibroblasts were decreased in vitamin A-deficient mice, suggesting alterations in colonic crypt niche function. Thus, vitamin A inhibited colitis and the development of colorectal cancer.

Immunohistochemical Characterization of a Renal Nephroblastoma in a Trp53-mutant and Prolyl Isomerase 1-deficient Mouse

A nephroblastoma is a tumor arising from metanephric blastema occurring in childhood. Among laboratory rodents, nephroblastoma has been frequently reported in rats, but it remains exceedingly rare in mice. The present work describes a nephroblastoma in a young mouse homozygous for the specific Trp53 R172H point mutation coupled with targeted deletion of the Pin1 gene. The affected kidney was effaced by a biphasic tumor with an epithelial component arranged in tubules surrounded by nests of blastemal cells. Immunohistochemically, the neoplasm was diffusely positive for Wilms’ tumor antigen. The epithelial component expressed markers of renal tubular differentiation including wide-spectrum cytokeratin, E-cadherin and folate-binding protein. Furthermore, the neoplasm exhibited a high proliferative index and diffuse nucleocytoplasmic β-catenin expression. Based on histological and immunohistochemical features, a diagnosis of nephroblastoma potentially associated with Trp53 loss and oncogenic β-catenin activation has been proposed.

The effect of vitamin A deficiency in maternal rats on tumor formation in filial rats

PURPOSE

We established a vitamin A-deficient (VAD) model of pregnant rats to evaluate the effect of vitamin A deficiency in maternal rats on tumor formation in filial rats.

METHODS

Ten pregnant Wistar rats were divided into 2 groups: (1) VAD group, 6 rats were given nonvitamin A diet from 2 weeks before mating till delivery and (2) normal diet (ND) group, 4 rats were given normal diet. Twenty random neonatal rats from each group were killed on the next day of delivery. The rest neonates were given normal diet for 1 year until killed. Serum levels of vitamin A, morphology of the kidney, incidence of tumor formation, and retinoid X receptor (RXR) alpha messenger RNA (mRNA) expression in renal tissue were assessed for the filial rats.

RESULTS

Fifty-six and 49 neonatal rats were born for VAD group and ND group, respectively. The detection rate of nephrogenic rests (NRs) from neonates in VAD group (50%) was significantly higher than that in ND group (20%; P < .05). The incidence of nephroblastoma was 13.9% in filial rats of VAD group and 0% for ND group. The detection rate of NRs for filial rats of VAD group (30.6%) was significantly higher than that of ND group (6.9%; P < .01). The expression of RXRalpha mRNA in tumor tissue of the filial rats of VAD group (3.17 +/- 0.15) was significantly lower than that in kidney tissue of ND group (3.58 +/- 0.20; P < .01).

CONCLUSION

Deficiency in vitamin A for pregnant rats resulted in renal dysplasia, increased NRs, and higher incidence of nephroblastoma.