Gonadal steroids block the calpain-1-dependent intrinsic pathway of apoptosis in an experimental rat stroke model.
OBJECTIVES
Apoptosis plays an important role in the progression of the ischemic penumbra after reperfusion. Estrogen and progesterone have neuroprotective effects against ischemic brain damage, however the exact mechanisms of neuroprotection and signaling pathways is not completely understood. In this study, we investigated the possible regulatory effects of a combined steroid treatment on extrinsic and intrinsic apoptotic signaling pathways after cerebral ischemia.


METHODS
Adult male Wistar rats were subjected to transient middle cerebral artery occlusion (tMCAO) using an intraluminal filament technique for 1 h followed by 23 h reperfusion. Estrogen and progesterone were immediately injected after tMCAO subcutaneously. Sensorimotor functional tests and the infarct volume were evaluated 24 h after ischemia. Protein expression of calpain-1 and Fas receptor (FasR), key members of intrinsic and extrinsic apoptosis, were determined in the penumbra region of the ischemic brain using western blot analysis, immunohistochemistry, and TUNEL staining.


RESULTS
Neurological deficits and infarct volume were significantly reduced following hormone therapy. Calpain-1 up-regulation and caspase-3 activation were apparent 24 h after ischemia in the peri-infarct area of the cerebral cortex. Steroid hormone treatment reduced infarct pathology and attenuated the induction of both proteases. FasR protein levels were not affected by ischemia and hormone application.


CONCLUSION
We conclude that a combined steroid treatment inhibits ischemia-induced neuronal apoptosis through the regulation of intrinsic pathways.
['Vahidinia|Zeinab|Z|', 'Alipour|Nasim|N|', 'Atlasi|Mohammad Ali|MA|', 'Naderian|Homayoun|H|', 'Beyer|Cordian|C|', 'Azami Tameh|Abolfazl|A|']
D000818:Animals D017209:Apoptosis D020520:Brain Infarction D002154:Calpain D002540:Cerebral Cortex D002560:Cerebrovascular Circulation D004195:Disease Models, Animal D005904:Glial Fibrillary Acidic Protein D020287:In Situ Nick-End Labeling D020244:Infarction, Middle Cerebral Artery D017078:Laser-Doppler Flowmetry D008297:Male D010751:Phosphopyruvate Hydratase D051381:Rats D017208:Rats, Wistar D015398:Signal Transduction D018709:Statistics, Nonparametric D013256:Steroids
Apoptosis Estrogen Progesterone tMCAO Calpain-1 CBF, Cerebral blood flow CCA, Common carotid artery CNS, Central nervous system DISC, Death inducing signaling complex FasR, Fas receptor GFAP, Glial fibrillary acidic protein HRP, Horseradish peroxidase I/R, Ischemia/reperfusion ICA, Internal carotid artery IHC, Immunohistochemistry MCA, Middle cerebral artery MCAO, Middle cerebral artery occlusion NeuN, Neuronal nuclear antigen PBS, Phosphate-buffered saline PU, Perfusion units PVDF, Polyvinylidene fluoride RIPA, Radioimmunoprecipitation assay ROS, Reactive oxygen species SDS, Sodium dodecyl sulfate TBI, Traumatic brain ischemia TNF, Tumor necrosis factor TTC, Triphenyltetrazolium chloride TUNEL, Terminal deoxynucleotidyltransferase (TdT)-mediated dUTP-biotin nick-end labeling tMCAO, transient middle cerebral artery occlusion