Assessment of the Effects of Stretch-Injury on Primary Rat Microglia
Abstract
Mechanical stretch-injury is a prominent force involved in the etiology of traumatic brain injury (TBI). It is known to directly cause damage and dysfunction in neurons, astrocytes, and endothelial cells. However, the deleterious effects of stretch-injury on microglia, the brains primary immunocompetent cell, are currently unknown. The Cell Injury Controller II (CICII), a validated model of cellular neurotrauma, induced a mechanical stretch-injury in primary rat microglia. Statistical analysis utilized student test and one and two way-ANOVAs with Tukey's and Sidak's multiple comparisons, respectively. Cells exposed to stretch-injury showed no signs of membrane permeability, necrosis, or apoptosis, as measured by media-derived lactate dehydrogenase (LDH) and cleaved-caspase 3 immunocytochemistry, respectively. Interestingly, injured cells displayed a functional deficit in nitric oxide (NO) production, identified by a media assay, at 6, 12, 18, and 48 hours post-injury. Coinciding with the decreased media levels of NO, iNOS (inducible nitric oxide synthase) protein expression was significantly decreased at twelve hours after injury. Furthermore, gene expression analysis revealed the expression of inflammatory cytokines IL-6 and IL-10 and enzyme arginase-1 was significantly down-regulated at 12 hours post-injury. Using a cell exclusion zone assay, time-course evaluation of microglial cell migration showed stretch-injured cells display decreased migration into the exclusion zone at 48 and 72 hours post-stretch. Lastly, coinciding with the functional immune deficits was a significant change in morphology, with process length decreasing and cell diameter increasing following an injury at 12 hours. Taken together, the data demonstrate that stretch-injury produces significant alterations in microglial morphology and function, which may have a marked impact on their response to injury or their interaction with other cells.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 19, 2021
- Accession Number
- AD1186133
Entities
People
- Michael C. Shaughness
Organizations
- Uniformed Services University of the Health Sciences