ABSTRACT
The gene for myelencephalon-specific protease (MSP) is a member of the kallikrein gene family and in rats is expressed mainly in the central nervous system. Its function and alteration in brain injury have not yet been clarified. We examined the expression of MSP after cryogenic injury (CI) using in situ hybridization, immunohistochemistry, and Western blotting. Analysis of MSP mRNA by in situ hybridization revealed a higher level of expression around the cryogenic area than on the contralateral side at 2-7 days after CI, with peak expression occurring 7 days after CI. Immunohistochemical analysis demonstrated expression of MSP protein at 1 day after CI, in the same region in which MSP mRNA was observed, with peak expression again at 7 days after CI, in the area around the lesion. Double immunohistochemical labeling revealed that MSP was expressed mainly in oligodendrocytes. These results suggest that expression of MSP may be related to the turnover of myelin-associated proteins and extracellular matrix proteins after CI. The regulation of active MSP may be important in the physiological or pathological changes involved in remyelination or demyelination.
Subject(s)
Brain Injuries/enzymology , Nerve Fibers, Myelinated/enzymology , Oligodendroglia/enzymology , Parietal Lobe/enzymology , Parietal Lobe/injuries , Serine Endopeptidases/metabolism , Animals , Brain Injuries/genetics , Brain Injuries/physiopathology , Disease Models, Animal , Disease Progression , Extracellular Matrix Proteins/metabolism , Freezing , Immunohistochemistry , Male , Myelin Sheath/metabolism , Nerve Fibers, Myelinated/pathology , Parietal Lobe/pathology , RNA, Messenger/metabolism , Rats , Rats, Wistar , Serine Endopeptidases/geneticsABSTRACT
Glia maturation factor beta (GMFB) was identified as a growth and differentiation factor acting on neurons as well as glia. We investigated the expression of GMFB during 56 days after cryogenic brain injury, using immunohistochemistry, reverse transcriptase polymerase chain reaction (RT-PCR), Western blotting and enzyme immunoassay. Immunohistochemical analysis demonstrated that the GFAP-positive astrocytes around the lesion expressed GMFB protein, peaking 14 days after injury. Weak astrocytic expression of GMFB-immunoreactivity was seen in sham-operated animal brains. Cryogenic injury (CI) induced GMFB mRNA in the lesioned side after 7 days with a maximum at 14 days. Western blotting revealed the induction of GMFB protein starting 1 day after injury, and continuing until 14 days after injury. In the enzyme immunoassay, GMFB protein concentration peaked 14 days after injury in extracts from the injured side of the brain, whereas in serum it peaked 1 day after injury. These data indicate that the expression of GMFB increased in the astrocytes around the lesioned area after cortical cryogenic brain injury. These findings may provide new insight into GMFB function in pathological conditions following brain injury.
