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Abstract: TH-PO136

Autotomy of Primary Cilia in Ischemia-Reperfusion Injury: An Electron Microscopic Study

Session Information

  • AKI: Mechanisms - I
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Ahn, Kyu Youn, Chonnam National University, Gwangju, Jeollanam-do, Korea (the Republic of)
  • Park, Kwon Moo, Kyungpook National University, Daegu, Korea (the Republic of)
  • Han, Ki-Hwan, Ewha Womans University, Seoul, Korea (the Republic of)
Background

Primary cilia are present in renal tubular cells and can change in length under certain conditions. Acute renal ischemia-reperfusion injury (I/R injury) can shorten primary cilia. It has been proposed that cilia may be rapidly fragmented and excreted into the urine. The purpose of this study was to examine the process of cilia fragmentation under high-resolution microscopy.

Methods

Sprague-Dawley rats were subjected to 30 minutes of ischemia by clamping bilateral renal pedicles and 6 hours of reperfusion. Kidney tissues and urine samples were processed for light and electron microscopy. Acetylated α-tubulin antibodies were used to label the primary cilia, and specific marker proteins were used to differentiate the tubule segments.

Results

I/R injury resulted in cell damage mainly in the proximal tubule and collecting duct cells of the outer medulla, and significantly reduced the length of the primary cilia. In the proximal tubule, ciliary labeling was often located within the lumen. Some cilia remained on the surface of detached aquaporin 1-positive cells, while others were disconnected from the tubular cells. On the other hand, in the collecting duct, most of the cilia detected in the lumen were independently labeled regardless of the detached cells. Field emission scanning electron microscope (FE-SEM) revealed that the cilia fragmentation was related to the 'bulging', in which a portion of the cilia sprouts. The bulging of the cilia was not limited to the tip end and appeared as a single or multiple. Most of the sprouting parts were spherical or oval, and the size varied from about 90 to 280 nm.

Conclusion

These results demonstrate that the cilia fragments induced by I/R injury can originate from several different tubules. The autotomy of primary cilia may be specifically related to partial sprouting and regulated by dynamic physiological processes.
This work was supported by funds from the National Research Foundation of Korea (NRF-2017R1D1A1B03030573 & 2020R1A2C1100184).

Funding

  • Government Support – Non-U.S.