Impairments of cerebral blood flow microcirculation in rats brought on by cardiac cessation and respiratory arrest.

Gennadii Piavchenko,Viktor Dremin,Ksenia Kandurova,Valery Shupletsov,Evgeniya Seryogina,Alexander Bykov,Alexander Alekseyev,Igor Kozlov,Sergey Kuznetsov,Igor Meglinski,Dmitry Stavtsev,Andrey Dunaev,Konstantin Lapin

doi:10.1002/jbio.202100216

Abstract

The impairments of cerebral blood flow microcirculation brought on by cardiac and respiratory arrest were assessed with multi-modal diagnostic facilities, utilising laser speckle contrast imaging, fluorescence spectroscopy and diffuse reflectance spectroscopy. The results of laser speckle contrast imaging show a notable reduction of cerebral blood flow in small and medium size vessels during a few minutes of respiratory arrest, while the same effect was observed in large sinuses and their branches during the circulatory cessation. Concurrently, the redox ratio assessed with fluorescence spectroscopy indicates progressing hypoxia, NADH accumulation and increase of FAD consumption. The results of diffuse reflectance spectra measurements display a more rapid grow of the perfusion of deoxygenated blood in case of circulatory impairment. In addition, consequent histopathological analysis performed by using new tissue staining procedure developed in-house. It shows notably higher reduction of size of the neurons due to their wrinkling within brain tissues influenced by circulation impair. Whereas, the brain tissues altered with the respiratory arrest demonstrate focal perivascular oedema and mild hypoxic changes of neuronal morphology. Thus, the study suggests that consequences of a cessation of cerebral blood flow become more dramatic and dangerous compare to respiratory arrest.

Highlights

Nowadays, prediction of early damage and microstructural reorganisation of cerebral tissues composition is crucial for numerous acute states, and especially those associated with a risk of brain death
We combined use of modern photonics-based modalities, such as laser speckle contrast imaging (LSCI), fluorescence spectroscopy (FS) and diffuse reflectance spectroscopy (DRS), the impairments of cerebral blood flow microcirculation brought by cardiac cessation and respiratory arrest are comparatively investigated
Whereas in small vessels the intensity of blood microcirculation decreasing after first minute is preserved both in case of respiratory arrest and cardiac cessation

Summary

Introduction

Prediction of early damage and microstructural reorganisation of cerebral tissues composition is crucial for numerous acute states, and especially those associated with a risk of brain death. We combined use of modern photonics-based modalities, such as laser speckle contrast imaging (LSCI), fluorescence spectroscopy (FS) and diffuse reflectance spectroscopy (DRS), the impairments of cerebral blood flow microcirculation brought by cardiac cessation and respiratory arrest are comparatively investigated. LSCI is well-known imaging modality [2], and used extensively in a number of blood microcirculation studies, including those of tumour angiogenesis [3], cutaneous vessels reaction to allergens [4, 5], skin complication of diabetes [6], respiratory-related blood flow oscillations [7], and visualisation of cerebral vascular network [8]. It has been demonstrated that with a combined application of LSCI and intravital fluorescence imaging the transcranial visualisation of brain's vascular bed can be performed in terms of blood flow within single arteries and veins [9,10,11]. When FS and DRS are successfully utilised for monitoring metabolic and morphological changes in biological tissues in vivo [13]

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