Combining systemic and stereotactic MEMRI to detect the correlation between gliosis and neuronal connective pathway at the chronic stage after stroke.
The early dysfunction and subsequent recovery after stroke, characterized by the destruction and remodeling of connective pathways between cortex and subcortical regions, is associated with neuroinflammation. As major components of the inflammatory process, reactive astrocytes have double-edged effects on pathological progression. The temporal patterns of astrocyte and neuronal pathway activity can be revealed by systemic and stereotactic manganese-enhanced magnetic resonance imaging (MEMRI), respectively. In the present study, we aimed to detect an association between astrocyte activity and recovery of neuronal connective pathways by combining systemic with stereotactic MEMRI.



Fifty adult rats, divided into two groups, underwent a 60-min occlusion of the middle cerebral artery. The groups were given either a systemic administration or stereotactic injection of MnCl2 at 1, 3, 7, and 14 days after stroke and underwent MRI 4 and 2 days later, respectively. Immunofluorescence (IF) of group 1 was conducted to corroborate the results. Repetitive behavioral testing was also performed with all rats at 1, 3, 7, and 14 days to obtain a functional score.



Ring- or crescent-shaped enhancements formed in the striatal peri-infarct regions (STR) at 11 and 18 days. This was concurrent with the activity of glial fibrillary acidic protein (GFAP)-positive astrocytes, which mainly localized at the peri-infarct region and significantly increased in number at 11 and 18 days after stroke. Microglia/macrophages, detected by IF, mainly localized in the lesion core, rather than in the region of enhancement. The ipsilateral substantia nigra (SN) revealed Mn-related signal enhancement reduction and subsequent signs of the recovery process at 3 to 5 days and 9 to 16 days, respectively. Behavioral testing showed that sensorimotor functions were initially disturbed, but subsequently recovered at 7 and 14 days.



We found a positive temporal correlation between astrogliosis and the recovery of neuronal connective pathways at the chronic stage by using the in vivo method of MEMRI. Our results highlighted the potential contribution of astrocytes to the neuronal recovery of these connective pathways.
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
Xiao-Zhu
XZ
Hao
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
Le-Kang
LK
Yin
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
Xiao-Xue
XX
Zhang
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
Jia-Qi
JQ
Tian
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
Chan-Chan
CC
Li
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
Xiao-Yuan
XY
Feng
Institutes of Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.
Min
M
Jiang
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, 200040, China. yym9876@sohu.com.
Yan-Mei
YM
Yang
D000704:Analysis of Variance; D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D002712:Chlorides / Q000494:pharmacology* / Q000627:therapeutic use; D004195:Disease Models, Animal; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000209:etiology; D020244:Infarction, Middle Cerebral Artery / Q000150:complications* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D008345:Manganese / Q000493:pharmacokinetics*; D017895:Manganese Compounds / Q000494:pharmacology* / Q000627:therapeutic use; D009043:Motor Activity / Q000187:drug effects; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D013997:Time Factors
D039481:CD11b Antigen; D002712:Chlorides; D005904:Glial Fibrillary Acidic Protein; D017895:Manganese Compounds; D008345:Manganese; D010751:Phosphopyruvate Hydratase; C025340:manganese chloride
Astrogliosis; MEMRI; Microglia/macrophage; Neuroinflammation; Neuronal connective pathway; Stroke