Activated protein C reduces endotoxin-induced white matter injury in the developing rat brain.
Periventricular leukomalacia (PVL), the dominant form of brain injury in premature infants, is characterized by white matter injury (WMI) and is associated with cerebral palsy. The pathogenesis of PVL is complex and likely involves ischemia/reperfusion, free radical formation, excitotoxicity, impaired regulation of cerebral blood flow, a procoagulant state, and inflammatory mechanisms associated with maternal and/or fetal infection. Using an established animal model of human PVL, we investigated whether activated protein C (APC), an anti-coagulant factor with anti-inflammatory, anti-apoptotic, anti-oxidant, and cytoprotective activities, could reduce endotoxin-induced WMI in the developing rat brain. Intraperitoneal injections of lipopolysaccharide (LPS) (0.5 mg/kg body weight) were given at embryonic days 18 (E18) and 19 (E19) to pregnant Sprague-Dawley rats; control rats were injected with sterile saline. A single intravenous injection of recombinant human (rh) APC (0.2 mg /kg body weight) was given to pregnant rats following the second LPS dose on embryonic day 19 (E19). Reduced cell death in white matter and hypomyelination were shown on TUNEL and myelin basic protein (MBP) staining, respectively, on late postnatal days (P7) in APC-treated groups. There were significantly fewer TUNEL+nuclei in the periventricular WM in the APC+LPS group than in the untreated LPS group. Compared to the APC+LPS and control group, MBP expression was weak in the LPS group on P7, indicating endotoxin-induced hypomyelination in the developing rat brain. APC attenuated the LPS-induced protein expression of inflammatory cytokines, tumor necrosis factor-alpha, and interleukin-6, as evaluated by ELISA in neonatal rat brains. A single intraperitoneal injection of rhAPC (0.2 mg/kg body weight) to neonatal rats on P1 also had similar protective and anti-inflammatory effects against maternally administered LPS. Collectively, these data support the hypothesis that APC may provide protection against an endotoxin-evoked inflammatory response and WMI in the developing rat brain. Moreover, our results suggest that the possible use of APC in treatment of preterm infants and pregnant women with maternal or placental infection may minimize the risk of PVL and cerebral palsy.
Yesilirmak
Didem Cemile
DC
Department of Pediatrics, School of Medicine, Dokuz Eylul, University, Inciralti, 35340, Izmir, Turkey.
Kumral
Abdullah
A
Baskin
Huseyin
H
Ergur
Bekir Ugur
BU
Aykan
Simge
S
Genc
Sermin
S
Genc
Kursad
K
Yilmaz
Osman
O
Tugyan
Kazim
K
Giray
Ozlem
O
Duman
Nuray
N
Ozkan
Hasan
H
D000818:Animals; D000831:Animals, Newborn; D000925:Anticoagulants / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000187:drug effects* / Q000254:growth & development / Q000503:physiopathology; D020806:Central Nervous System Bacterial Infections / Q000150:complications / Q000503:physiopathology; D002547:Cerebral Palsy / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D004195:Disease Models, Animal; D004660:Encephalitis / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D004731:Endotoxins / Q000037:antagonists & inhibitors* / Q000633:toxicity; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000378:metabolism; D007275:Injections, Intravenous; D007969:Leukomalacia, Periventricular / Q000188:drug therapy* / Q000503:physiopathology / Q000517:prevention & control; D008070:Lipopolysaccharides / Q000494:pharmacology; D004676:Myelin Basic Protein / Q000187:drug effects / Q000378:metabolism; D009413:Nerve Fibers, Myelinated / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D018696:Neuroprotective Agents / Q000378:metabolism / Q000494:pharmacology / Q000627:therapeutic use; D011247:Pregnancy; D011486:Protein C / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology / Q000627:therapeutic use
D000925:Anticoagulants; D004731:Endotoxins; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D004676:Myelin Basic Protein; D018696:Neuroprotective Agents; D011486:Protein C; D011994:Recombinant Proteins