High Resolution Intravital Imaging of the Renal Immune Response to Injury and Infection in Mice

Abstract

We developed an experimental set up that enables longitudinal studies of immune cell behavior in situ in the challenged as well as unchallenged kidney of anesthetized mice over several hours. Using highly controlled vacuum to stabilize the kidney, the superficial renal cortex could continuously be visualized with minimal disruption of the local microenvironment. No visible changes in blood flow or neutrophils and macrophages numbers were observed after several hours of visualizing the unchallenged kidney, indicating a stable tissue preparation without apparent tissue damage. Applying this set up to monocyte/macrophage (CX 3 CR1 GFP/+ ) reporter mice, we observed the extensive network of stellate-shaped CX 3 CR1 positive cells (previously identified as renal mononuclear phagocytes). The extended dendrites of the CX 3 CR1 positive cells were found to bridge multiple capillaries and tubules and were constantly moving. Light induced sterile tissue injury resulted in rapid neutrophil accumulation to the site of injury. Similarly, microinfusion of uropathogenic Escherichia coli into a single nephron induced a rapid and massive recruitment of neutrophils to the site of infection, in addition to active bacterial clearance by neutrophils. In contrast, the kidney resident mononuclear phagocytes were observed to not increase in numbers or migrate toward the site of injury or infection. In conclusion, this model allows for longitudinal imaging of responses to localized kidney challenges in the mouse.

Fluorescence Microscopy—An Outline of Hardware, Biological Handling, and Fluorophore Considerations

“…Transgenic animals modified to express fluorescently tagged proteins provide a true in vivo environment for evaluating various cellular processes, with constitutive replenishment of fluorescently labelled proteins enabling long-term tracing in a cell- and tissue-specific manner. This technique mainly makes use of small organisms, such as fruit flies [ 106 , 107 , 108 ], zebrafish [ 95 , 109 , 110 ], and mice [ 111 , 112 ], due to their short generation times, established genetic lines, and relatively low cost. Subcutaneous and orthotopic xenograft models used in intravital studies can accurately provide insights into tumour heterogeneity and responses to drug treatments [ 113 , 114 ].…”

The frontier of live tissue imaging across space and time

“…In the peritoneal cavity, different organs, including the small intestine, colon, liver, kidney, spleen, and pancreas, have been visualized at single-cell resolution using various abdominal windows (Bernier-Latmani and Petrova, 2016). Cell vitality and apoptosis, fluid transport, receptor-mediated endocytosis, blood flow, and recruitment of immune cells have been characterized using these intravital approaches (Kitamura et al, 2017;Nirmalraj et al, 2018;Sedin et al, 2019;Small et al, 2016;Zhang et al, 2014). The dynamics of the intestinal stem cell niche have been visualized using Lgr5-confetti mice with Lgr5+ stem cell labeling (Ritsma et al, 2014).…”

Effect of anticoagulant and platelet inhibition on the risk of bacteremia among patients with acute pyelonephritis: a retrospective cohort study

“…In rodents, vascular thrombus formation has been observed during experimental kidney infection [ 13 – 17 ]. We previously visualized clot formation in peritubular capillaries following a localized kidney tubule infection [ 14 – 16 ]. This clot formation appeared to be protective against urosepsis, as anticoagulant treatment delayed the initiation of clotting and resulted in systemic spread of bacteria [ 14 ].…”