Macrophages Rapidly Seal off the Punctured Zebrafish Larval Brain through a Vital Honeycomb Network Structure

Abstract

There is accumulating evidence that macrophages play additional important roles in tissue damage besides their typical phagocytosis. Although the aggregation of macrophages on injured sites has long been observed, few researchers have focused on the role of the overall structure of macrophage aggregation. In this study, we developed a standardized traumatic brain injury (TBI) model in zebrafish larvae to mimic edema and brain tissue spillage symptoms after severe brain trauma. Using time-lapse imaging, we showed that macrophages/microglia in zebrafish larvae responded rapidly and dominated the surface of injured tissue, forming a meaningful honeycomb network structure through their compact aggregation and connection. Disrupting this structure led to fatal edema-like symptoms with severe loss of brain tissue. Using the RNA-Seq, together with the manipulation of in vitro cell lines, we found that collagen IV was indispensable to the formation of honeycomb network structures. Our study thus revealed a novel perspective regarding macrophages forming a protective compact structure with collagen IV. This honeycomb network structure acted as a physical barrier to prevent tissue loss and maintain brain homeostasis after TBI. This study may provide new evidence of macrophages’ function for the rapid protection of brain tissue after brain injury.

Rapid altitude displacement induce zebrafish appearing acute high altitude illness symptoms

“…To address the massive flaws in modeling or screening drugs such as mice and rats, AHAI in zebrafish model animal was researched, which have a comparable blood-brain barrier, strong genetic similarities and respiratory metabolism to humans [ [26] , [27] , [28] , [29] , [30] ]. At the same time, zebrafish respond to many pathological factors with robust oxidative stress [ 47 ].…”

“…At the same time, zebrafish is also a classic animal model for studying blood-brain barrier integrity and local pathology ( e.g. edema) in vivo [ 29 , 30 ]. Recognizing these advantages, a static self-assembled water vacuum transparent chamber equipment was designed to induce AHAI symptoms in zebrafish to provide a high-throughput animal model for future drug screening of AHAI ( Fig.…”