Acute and Chronic Models of Hyperglycemia in Zebrafish: A Method to Assess the Impact of Hyperglycemia on Neurogenesis and the Biodistribution of Radiolabeled Molecules

Abstract

Hyperglycemia is a major health issue that leads to cardiovascular and cerebral dysfunction. For instance, it is associated with increased neurological problems after stroke and is shown to impair neurogenic processes. Interestingly, the adult zebrafish has recently emerged as a relevant and useful model to mimic hyperglycemia/ diabetes and to investigate constitutive and regenerative neurogenesis. This work provides methods to develop zebrafish models of hyperglycemia to explore the impact of hyperglycemia on brain cell proliferation under homeostatic and brain repair conditions. Acute hyperglycemia is established using the intraperitoneal injection of D-glucose (2.5 g/kg bodyweight) into adult zebrafish. Chronic hyperglycemia is induced by immersing adult zebrafish in D-glucose (111 mM) containing water for 14 days. Blood-glucose-level measurements are described for these different approaches. Methods to investigate the impact of hyperglycemia on constitutive and regenerative neurogenesis, by describing the mechanical injury of the telencephalon, dissecting the brain, paraffin embedding and sectioning with a microtome, and performing immunohistochemistry procedures, are demonstrated. Finally, the method of using zebrafish as a relevant model for studying the biodistribution of radiolabeled molecules (here,[18 F]-FDG) using PET/CT is also described.

TSA-PACT: a method for tissue clearing and immunofluorescence staining on zebrafish brain with improved sensitivity, specificity and stability

“…7 C). We generated a chronic hyperglycemia injury model by keeping the fish in high glucose for 14 days, which could induce metabolic disorders, affecting brain inflammation and neurogenesis [ 30 , 41 ]. We then performed cell counting in the telencephalon, which is sensitive to chronic hyperglycemia (Fig.…”

Insulin signaling promotes neurogenesis in the brain of adult zebrafish

“…Given that we showed here the possible impact of insulin on neurogenesis in zebrafish, it can be supposed conversely that insulin disturbances may contribute to the development and progression of brain disorders (Ghasemi et al., 2013). Metabolic disorders including diabetes and obesity are characterized by insulin desensitization (Wondmkun, 2020) and have been associated with impaired neurogenesis as described in zebrafish and mammals (Bayram et al., 2022; Dorsemans et al., 2017; Dos Santos et al., 2020; Gence et al., 2022; Ghaddar et al., 2020; Ghaddar et al., 2021; Kaiyala et al., 2000). Some studies reported that insulin resistance (with and without metabolic alterations) was closely related with the development of neurodegenerative and neuropsychiatric diseases such as Alzheimer's and Parkinson's diseases (Hölscher, 2020).…”

“…The alteration in the PI3K/AKT/GSK3 (Phosphatidylinositol 3‐kinase/Protein kinase B/Glycogen synthase kinase 3) pathway was also reported in the pathogenesis of brain diseases knowing that these molecules play a crucial role in neuroplasticity by regulating cell survival, neurogenesis, neuronal proliferation and differentiation, and synaptic plasticity (Long et al., 2021; Matsuda et al., 2019). It will be consequently interesting to investigate the specific role of peripheral and central insulin on brain functions and plasticity using specific obese/overweight and/or hyperglycemic zebrafish models (Dorsemans et al., 2017; Gence et al., 2022; Ghaddar et al., 2021).…”

“…Brain cell proliferation analysis was done according to previous protocols (Dorsemans, Lefebvre d'Hellencourt et al., 2017; Gence et al., 2022). Briefly, adult zebrafish brains were rehydrated, permeabilized with PTw (1× PBS containing 0.1% Tween 20, pH 7.4) and embedded in 2% agarose before performing 50‐μm‐thick sections using a vibratome (VT1000S, Leica).…”