Immunohistochemical analysis for acetylcholinesterase and choline acetyltransferase in mouse cerebral cortex after traumatic brain injury

• Published in: Journal of Veterinary Medical Science Vol. 82; no. 6; pp. 827 - 835
• Main Authors: HORIO, Tomoyo, OZAWA, Aisa, KAMIIE, Junichi, SAKAUE, Motoharu
• Format: Journal Article
• Language: English
• Published: Japan JAPANESE SOCIETY OF VETERINARY SCIENCE 2020; Japan Science and Technology Agency; The Japanese Society of Veterinary Science
• Subjects: acetylcholine; Acetylcholinesterase; Acetylcholinesterase - metabolism; Acetyltransferase; Anatomy; Animals; Antigens, CD - metabolism; Antigens, Differentiation, Myelomonocytic - metabolism; Astrocytes; Brain - enzymology; Brain - metabolism; Brain Injuries, Traumatic - physiopathology; Cell death; Central nervous system; Cerebral cortex; Cerebral Cortex - enzymology; Cerebral Cortex - metabolism; Choline; choline acetyltransferase; Choline O-acetyltransferase; Choline O-Acetyltransferase - metabolism; Enzymes; Glial cells; Glial Fibrillary Acidic Protein; Immunohistochemistry; Male; Mice, Inbred C57BL; Microglia; Neuroglia - metabolism; Neuroglia - pathology; Neuronal-glial interactions; Traumatic brain injury; traumatic brain injury; acetylcholinesterase; choline acetyltransferase; acetylcholine; immunohistochemistry
• DOI: 10.1292/jvms.19-0551
• ISSN: 0916-7250; 1347-7439

The regulation of glial cells, especially astrocytes and microglia, is important to prevent the exacerbation of a brain injury because over-reactive glial cells promote neuronal death. Acetylcholine (ACh), a neurotransmitter synthesized and hydrolyzed by choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), respectively, in the central nervous system, has the potential to regulate glial cells’ states, i.e., non-reactive and reactive states. However, the expression levels of these ACh-related enzymes in areas containing reactive glial cells are unclear. Herein we immunohistochemically investigated the distributions of AChE and ChAT with reactive glial cells in the cryo-injured brain of mice as a traumatic brain injury model. Immunohistochemistry revealed AChE- and ChAT-immunopositive signals in injured areas at 7 days post-injury. The signals were observed in and around glial fibrillary acidic protein (GFAP)- or CD68-immunopositive cells, and the numbers of cells doubly positive for GFAP/AChE, GFAP/ChAT, CD68/AChE, and CD68/ChAT were significantly increased in injured areas compared to sham-operated areas. Enzyme histochemistry for AChE showed intensely positive signals in injured areas. These results suggest that reactive astrocytes and microglia express and secrete AChE and ChAT in brain-injury areas. These glial cells may adjust the ACh concentration around themselves through the regulation of the expression of ACh-related enzymes in order to control their reactive states.