Title Renal impairment with sublethal tubular cell injury in a chronicliver disease mouse model

The pathogenesis of renal impairment in chronic liver diseases (CLDs) has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy), autophagy, and oxidative stress were studied longitudinally in DDCand standard diet–fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the pathophysiological mechanisms of sublethal tubular cell injury. PLOS ONE | DOI:10.1371/journal.pone. 0146871 January 11, 2016 1 / 22 OPEN ACCESS Citation: Ishida T, Kotani H, Miyao M, Kawai C, Jemail L, Abiru H, et al. (2016) Renal Impairment with Sublethal Tubular Cell Injury in a Chronic Liver Disease Mouse Model. PLoS ONE 11(1): e0146871. doi:10.1371/journal.pone. 0146871 Editor: Utpal Sen, University of Louisville, UNITED STATES Received: September 21, 2015 Accepted: December 25, 2015 Published: January 11, 2016 Copyright: © 2016 Ishida et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: This study was supported by a grant from the Japan Society for the Promotion of Science (https://www.jsps.go.jp/english/index.html) KAKENHI (Grant-in-Aid for Scientific Research) Grant Number 26460877 to HK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist.