Contents

Interpreting Cellular Recovery in Acute Spinal Cord Injury: Microglial Marker Return, Progenitor Responses, and Endothelial Transience

Susan L. Orloff1, Ahmed Mohamed Alireza1
1Department of Surgery, Oregon Health and Science University, Portland, OR, USA

Abstract

Microglial marker restoration, oligodendroglial differentiation-associated expression, and declining endothelial tip-cell representation describe different aspects of the response to spinal cord contusion. This analytical review examines whether they provide equivalent evidence of cellular recovery in GSE162610 and its accompanying cytometric and anatomical observations. The atlas contains 66,178 cells from ten preparations and sixteen female C57BL/6J mice, sampled from uninjured spinal cord and at one, three, and seven days after T8 contusion. Six preparations combined two spinal cords and included astrocyte enrichment. P2RY12-high/MSR1-low microglia constituted more than 90% of microglia before injury and approximately 20% at one day, followed by partial restoration at seven days. CD63-high macrophages separated into CD11b-medium/APOE-low chemotaxis-inducing and CD11b-high/APOE-high inflammatory phenotypes. OPC-A persisted across the sampling interval, whereas OPC-B was most prominent at one day and declined by seven days. Canal-associated Crym expression and the Apln-positive endothelial response were greatest early after injury. Transition kernels, absorption probabilities, finite-step occupancy, and preparation means are interpreted algebraically; numerical CellRank probabilities are not estimated. The weighted-mean identity establishes that changing state proportions can alter a preparation average without changing probabilities within comparable states. Microglial marker return therefore indicates partial phenotypic restoration, oligodendroglial expression identifies differentiation-associated states, and endothelial transience describes temporary activation. These observations are not equivalent measures of repair. Their overlapping timing neither establishes a common cellular trajectory nor substitutes for measurements of myelin formation, perfusion, or neurological function.

Keywords: spinal cord injury, single-cell RNA sequencing, microglia, macrophages, oligodendrocyte progenitors, endothelial tip cells, CellRank 2, GSE162610
Copyright © 2026 Susan L. Orloff, Ahmed Mohamed Alireza. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.