Noreldin Ahmed E, Elewa Yaser Hosny Ali, Kon Yasuhiro, Warita Katsuhiko, Hosaka Yoshinao Z
Veterinary Anatomy, Faculty of Agriculture, Tottori University, Tottori, Tottori, Japan; Department of Histology and Cytology, Faculty of Veterinary Medicine, The Scientific Campus, Damanhour University, Damanhour, Egypt.
Laboratory of Anatomy, Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan; Department of Histology and Cytology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt.
Acta Histochem. 2018 May;120(4):323-328. doi: 10.1016/j.acthis.2018.03.001. Epub 2018 Mar 11.
Osteoblast activating peptide (OBAP) is a newly discovered peptide detected in the rat stomach, which has a major role in osteogenesis. Recently, we revealed its localization in the parietal cells of the rat stomach. There have been no data regarding OBAP expression in the kidney, despite its role in calcium reabsorption in renal tubules. The current study aimed to inspect the expression of OBAP in the kidney of twelve 10-week-old male C3H/HeNJc1 mice using immunohistochemistry, and immunoelectron microscopic localization. The immunohistochemical investigation revealed an OBAP positive reaction mainly in the medulla, which was stronger than the cortex of the kidney and was concentrated in the distal convoluted tubules (DCT), connecting tubules (CT), and the thick limbs of the loop of Henle (HL). Moreover, we clarified that the OBAP was co-distributed with ghrelin and calbindin (markers of the DCT). Interestingly, immunoelectron microscopy demonstrated that OBAP was concentrated in the mitochondrial inner membrane of the DCT and CT. Based on these results, it was concluded that the mitochondria of the DCT, CT, and HL of the mice kidney generate OBAP. Furthermore, our results suggest that OBAP might have a role in the regulation of calcium reabsorption by the renal tubule; however, further investigations are required to clarify this potential role.
成骨细胞激活肽（OBAP）是一种新发现的在大鼠胃中检测到的肽，它在骨生成中起主要作用。最近，我们揭示了它在大鼠胃壁细胞中的定位。尽管OBAP在肾小管钙重吸收中发挥作用，但关于其在肾脏中的表达尚无数据。本研究旨在使用免疫组织化学和免疫电子显微镜定位法检测12只10周龄雄性C3H/HeNJc1小鼠肾脏中OBAP的表达。免疫组织化学研究显示，OBAP阳性反应主要在髓质，比肾皮质更强，且集中在远曲小管（DCT）、连接小管（CT）和髓袢升支粗段（HL）。此外，我们明确OBAP与ghrelin和钙结合蛋白（DCT的标志物）共同分布。有趣的是，免疫电子显微镜显示OBAP集中在DCT和CT的线粒体内膜。基于这些结果，得出结论：小鼠肾脏的DCT、CT和HL的线粒体产生OBAP。此外，我们的结果表明OBAP可能在肾小管钙重吸收的调节中起作用；然而，需要进一步研究来阐明这一潜在作用。
