Effects of a high-sodium diet on renal tubule Ca2+ transporter and claudin expression in Wistar-Kyoto rats

• Yatabe, Midori Sasaki

• Yatabe, Junichi

• Takano, Kozue

• Murakami, Yuta

• Sakuta, Rina

• Abe, Sadahiko

• Sanada, Hironobu

• Kimura, Junko

• Watanabe, Tsuyoshi

抄録

type:Text

Background: Urinary Ca^{2+} excretion increases with dietary NaCl. NaCl-induced calciuria may be associated with hypertension, urinary stone formation and osteoporosis, but its mechanism and long-term effects are not fully understood. This study examined alterations in the expressions of renal Ca^{2+} transporters, channels and claudins upon salt loading to better understand the mechanism of salt-induced urinary Ca^{2+} loss. Methods: Eight-week old Wistar-Kyoto rats were fed either 0.3% or 8% NaCl diet for 8 weeks. Renal cortical expressions of Na+/Ca2+ exchanger 1 (NCX1), Ca^{2+} pump (PCMA1b), Ca^{2+} channel (TRPV5), calbindin-D28k, and claudins (CLDN-2, -7, -8, -16 and −19) were analyzed by quantitative PCR, western blot and/or immunohistochemistry. Results: Fractional excretion of Ca^{2+} increased 6.0 fold with high-salt diet. Renal cortical claudin-2 protein decreased by approximately 20% with decreased immunological staining on tissue sections. Claudin-16 and −19 expressions were not altered. Renal cortical TRPV5, calbindin-D28k and NCX1 expressions increased 1.6, 1.5 and 1.2 fold, respectively. Conclusions: Chronic high-salt diet decreased claudin-2 protein and increased renal TRPV5, calbindin-D28k, and NCX1. Salt loading is known to reduce the proximal tubular reabsorption of both Na+ and Ca^{2+}. The reduction in claudin-2 protein expression may be partly responsible for the reduced Ca^{2+} reabsorption in this segment. The concerted upregulation of more distal Ca^{2+}-transporting molecules may be a physiological response to curtail the loss of Ca^{2+}, although the magnitude of compensation does not seem adequate to bring the urinary Ca^{2+} excretion down to that of the normal-diet group.

収録刊行物

• BMC nephrology

  BMC nephrology 13 160-, 2012-12-02

  BioMed Central Ltd.

キーワード

• Calcium
• Sodium chloride
• Distal tubule
• Na+/Ca2+ exchanger
• Ca2+ channel
• Claudins

詳細情報

• CRID: 1050001337586529664
• NII論文ID: 120005294612
• NII書誌ID: AA12035314
• ISSN: 14712369
• DOI: 10.1186/1471-2369-13-160
• Web Site: http://ir.fmu.ac.jp/dspace/handle/123456789/354
• Web Site: http://link.springer.com/article/10.1186/1471-2369-13-160/fulltext.html
• Web Site: http://link.springer.com/content/pdf/10.1186/1471-2369-13-160.pdf
• Web Site: http://link.springer.com/content/pdf/10.1186/1471-2369-13-160
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
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