Hakan AY, Abdullah ORTADEVECİ, Duygu ASLAN

A Vitamininin Subteratojenik Dozlarının Sıçan Fetüs Böbreği Üzerine Etkileri: Stereolojik Bir Çalışma

Amaç: A vitamini (retinol) ve türevleri, fetüste normal embriyonik gelişim ve yetişkin organizmada hücre farklılaşmasının sürdürülmesi için gereklidir. Öte yandan aşırı dozda A vitamini alımının teratojenik etkilerinin olduğu bilinmektedir. Retinoik asit reseptörleri, ürogenital yapıların gelişiminde çok önemli bir rol oynar. Düşük ve orta doz retinolün üriner sistem üzerindeki etkilerine ilişkin yeterli çalışma yoktur. Çalışmamızın amacı orta ve düşük doz A vitamininin fetal böbrek üzerine etkilerini araştırmaktır. Materyal ve Metod: Gebe sıçanlar 6 gruba ayrıldı. Gebeliğin 10 ila 12. gününde (P10-P12). Birinci gruba 10.000 IU/kg, ikinci gruba 20.000 IU/kg, üçüncü gruba 30.000 IU/kg, dördüncü gruba 40.000 IU/kg ve beşinci gruba 50.000 IU/kg oral A vitamini verildi. Kontrol grubuna sadece 1 ml mısır yağı verildi. P19'da fetüsler sezaryen ile çıkarıldı. Fetüsler kalp perfüzyonu ile tespit edildi ve böbrekleri alındı. Histolojik ön aşamalardan sonra, kesitler hematoksilen ve eozin ile boyandı. Böbrek hacmi (V), birim alandaki glomerül sayısı (Na) ve glomerül çapı (D) stereolojik yöntemlerle hesaplandı. Sonuçlar istatistiksel olarak analiz edildi. Bulgular: 20.000, 30.000 ve 40.000 IU/kg gruplarının böbrek hacimleri diğer gruplara göre daha yüksekti. Ayrıca 50.000 IU/kg alan grubun NAg düzeylerinin diğer tüm gruplara göre daha düşük olduğu saptandı. Ayrıca 20.000, 30.000 ve 40.000 IU/kg A vitamini alan grupların NAg düzeyleri kontrol grubu ve 10.000 IU/kg alan gruba göre daha yüksekti. Deney gruplarının glomerül çapları kontrol grubundan farklı değilken, 20.000 ve 50.000 IU/kg retinol alan grubun glomerül çapları 10.000 ve 40.000 IU/kg A vitamini alan gruplardan daha büyüktü. Sonuç: 20.000 IU/kg A vitamini alan grubun daha yüksek V, NAg ve D değerleri göz önüne alındığında, bu dozun böbrek morfolojisi ve gelişimi üzerinde önemli bir etkisi olduğunu düşünülmektedir.

Anahtar Kelimeler:

Sıçan, Fetüs, Böbrek, A Vitamini, Teratojenler, Rats, Fetus, Kidney, Vitamin A, Teratogens

The Effects of Subteratogenic Vitamin A Doses on the Fetal Rat Kidney: A Stereological Study

Background: Vitamin A (retinol) and its derivatives are essential for maintaining cell differentiation in adult organisms as well as for normal embryonic development in fetuses. On the other hand, high amounts of vitamin A are known to be teratogenic. The formation of urogenital structures depends heavily on retinoic acid receptors. The effects of low and moderate dosages of retinol on the urinary system have not been adequately studied. The aim of our study was to investigate the effects of moderate and low doses of vitamin A on the fetal kidney. Materials and Methods: Pregnant rats were divided into 6 groups. On day 10 to 12 of pregnancy (P10-P12) the first group was administered 10000 IU/kg, the second group 20000 IU/kg, the third group 30000 IU/kg, the fourth group 40000 IU/kg and the fifth group 50000 IU/kg oral vitamin A. The control group only received 1 ml of corn oil on the same days. The fetuses were delivered via cesarean section at P19. The kidneys of the fetuses were removed after cardiac perfusion was used to fixate them. After histological preparation of the kidneys, the slides were stained with hematoxylin and eosin. By using stereological methods, the kidneys' volume (V), glomeruli per unit area (NAg), and glomeruli diameter (D) were all estimated. The results were statistically analyzed. Results: The renal volumes of the 20000, 30000 and 40000 IU/kg groups were higher than those of the other groups. It was also found that the NAg levels of the group receiving 50000 IU/kg Vitamin A were lower than those of all other groups. Moreover, the NAg levels of the groups receiving 20000, 30000 and 40000 IU/kg vitamin A were higher than those of the control group and the group receiving 10000 IU/kg. While the glomeruli diameters of the experimental groups were not different from those of the control group, the glomeruli diameters of the group receiving 20000 and 50000 IU/kg retinol were larger than those of the groups receiving 10000 and 40000 IU/kg vitamin A. Conclusions: Given the estimated higher V, Na, and D values of the group receiving 20000 IU/kg vitamin A, we can assume that this particular dose has a significant effect on renal morphology and development.

Keywords:

Rats, Fetus, Kidney, Vitamin A, Teratogens,

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1. Gerster H. Vitamin A-functions, dietary requirements and safety in humans. Int J Vit Nutr Res. 1997; 67(2):71–90.
2. Filteau SM, Tomkins AM. Vitamin A supplementation in developing countries. Arch Dis Child. 1995; 72(2):106–107.
3. World Health Organization. Global prevalence of vitamin A deficiency in populations at risk 1995-2005: WHO global da-tabase on vitamin A deficiency. 2009.
4. Sharma SC, Bonnar J, Dostalova L. Comparison of blood levels of vitamin A, beta-carotene and vitamin E in abruptio placentae with normal pregnancy. Int J Vit Nutr Res. 1986; 56(1):3-9.
5. Ortega RM, Andrés P, Martinez RM, Lopez-Sobaler AM. Vitamin A status during the third trimester of pregnancy in Spanish women: influence on concentrations of vitamin A in breast milk. Am J Clin Nutr. 1997; 66(3):564–568.
6. Deluca LM. Retinoids and their receptors in differentiation, embryogenesis, and neoplasia. FASEB J. 1991; 5(14):2924–2933.
7. Glass CK, Direnzo JAMES, Kurokawa R, Han Z. Regulation of gene expression by retinoic acid receptors. DNA Cell Biol. 1991; 10(9):623–638.
8. Lelièvre-Pégorier M, Vilar J, Ferrier ML, Moreau E, Freund N, Gilbert T et al. Mild vitamin A deficiency leads to inborn nephron deficit in the rat. Kidney Int. 1998; 54(5):1455-62.
9. Means L, Gudas L. The role of retinoids in vertebrate devel-opment. Ann Rev Biochem. 1995; 64(1):201–233.
10. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). Scientific opinion on dietary reference values for vit-amin A. EFSA journal. 2015; 13(3):4028.
11. Duester G. Retinoic acid synthesis and signaling during early organogenesis. Cell. 2008; 134(6):921-931.
12. Wilson JG, Roth CB, Warkany J. An analysis of the syndrome of malformations induced by maternal vitamin A deficiency. Effects of restoration of vitamin A at various times during gestation. Am J Anat. 1953; 92:189–217.
13. Rothman KJ, Moore LL, Singer MR, Nguyen USD, Mannino S, Milunsky A. Teratogenicity of high vitamin A intake. N Engl J Med. 1995; 35(3):1369–1373.
14. Shenefelt RE. Morphogenesis of malformations in hamsters caused by retinoic acid: Relation to dose and stage at treat-ment. Teratology. 1972; 5(1):103–118.
15. Ay H, Aslan D, Soztutar E, Yucel F. Low dosages of vitamin A may cause a decrease in the total neuron number of fetal hippocampal rat cells. Bratisl Lek Listy. 2020; 121(8):580-583.
16. Herman KW, Maran BW, Adrian SW, Aswin LM, Nicholas DH, John AG et al. Implication of Wt1 in the pathogenesis of nephrogenic failure in a mouse model of retinoic acid-induced caudal regression syndrome. Am J Pathol. 2005; 166(5):1295-1307.
17. Dame MC, Knutson D. Vitamin A in reproduction and devel-opment. Nutrients. 2011; 3(4):385-428.
18. Tulachan SS, Doi R, Kawaguchi Y. All-trans retinoic acid in-duces differentiation of ducts and endocrine cells by mes-enchymal/epithelial interactions in embryonic pancreas. Di-abetes. 2003: 52(1);76-84.
19. Nasser U, Tahir M. Effects of Vitamin A on Fetal Kidneys in Albino Mice: A Histological Study. Pakistan J Zool. 2012; 44(4):1045-1050.
20. Lee LM, Leung CY, Tang WW, Choi HL, Leung YC, McCaffery PJ et al. A paradoxical teratogenic mechanism for retinoic acid. Proc Natl Acad Sci. 2012; 109(34):13668-73.
21. Chen A, Liu Y, Lu Y, Lee K, He JC. Disparate roles of retinoid acid signaling molecules in kidney disease. Am J Physiol Re-nal Physiol. 2021; 320(5):F683-F692.
22. D'Agati VD, Chagnac A, De Vries AP, Levi M, Porrini E, Her-man-Edelstein M et al. Obesity-related glomerulopathy: cli-nical and pathologic characteristics and pathogenesis. Nat Rev Nephrol. 2016; 12(8):453-71.
23. Tobar A, Ori Y, Benchetrit S, Milo G, Herman-Edelstein M, Zingerman B et al. Proximal tubular hypertrophy and enlar-ged glomerular and proximal tubular urinary space in obese subjects with proteinuria. PLoS One. 2013; 8(9):e75547.
24. Amato D, Núñez-Ortiz A, Carmen Benítez-Flores J, Segura-Cobos D, López-Sánchez P, Vázquez-Cruz B. Role of Angio-tensin-(1-7) on Renal Hypertrophy in Streptozotocin-Induced Diabetes Mellitus. Pharm Pharmacol. 2016: 7(9):379-395.
25. Xu Q, Kopp JB. Retinoid and TGF-β families: crosstalk in development, neoplasia, immunity, and tissue repair. Semin Nephrol. 2012; 32(3):287-94.
26. Aslan D, Soztutar E, Ay H. Adverse effects of maternal retinyl palmitate, a vitamin A compound, on the fetal liver. Int J Vi-tam Nutr Res. 2022 Oct 6. doi: 10.1024/0300-9831/a000769. [Epub ahead of print].