Korean J Transplant.  2022 Nov;36(Supple 1):S380. 10.4285/ATW2022.F-5204.

In vivo imaging of renal microvasculature in murine ischemia-reperfusion injury models using optical coherence tomography angiography

• Cho JH
• Oh SH
• Kim YJ
• Ahn JS
• Yook JM
• Oh EJ
• Lee B
• Kang W
• Oh WY

• KMID: 2535224
• DOI: http://doi.org/10.4285/ATW2022.F-5204

Abstract

Background
Optical coherence tomography angiography (OCTA) is a non-invasive imaging technique that provides three-di-mensional structural and semi-quantitative imaging of the microvasculature in vivo. We developed an OCTA imaging protocol for the mouse kidney ischemia-reperfusion injury (IRI) model to investigate the correlation of the changes in renal microvasculature with ischemic damage.
Methods
A prototype SS-OCT system centered at 1300 nm with a 220.4 kHz A-scan rate was used for kidney imaging. Mice were divided into two groups according to the ischemic time; 10 and 35 minutes for the mild and moderate IRI groups. Each animal was imaged at baseline, during the ischemia, and at 1, 15, 30, 45, and 60 minutes after ischemia. An intensity decorrela-tion OCTA B-scan was computed from five B-scans acquired at the same position. OCTA images were constructed with 1.5-ms, 3.0-ms, and 5.8-ms interscan time, respectively, to calculate semi-quantitative flow index in the superficial (50–70 m) and deep (220–340 m) capillaries.
Results
The mild IRI group did not show significant flow index changes in superficial and deep layers. The moderate IRI group manifested a significantly decreased flow index from 15 minutes in the superficial layer and from 45 minutes in the deep layer, respectively. When comparing the two groups, superficial blood flow in the moderate group decreased significantly from 15 minutes, whereas no difference was observed in deep blood flow. Seven weeks after the IRI induction, the moderate IRI group showed lower kidney function and higher collagen deposition than the mild IRI group.
Conclusions
OCTA imaging of the murine IRI model could find the changes in superficial blood flow after ischemic injury. The decreased superficial blood flow rather than deep blood flow was associated with sustained dysfunction after IRI. Investigation of post-IRI renal microvascular response using OCTA could evaluate ischemic insult and predict kidney function.