Ultrastructural Changes Of Neuronal Mitochondria In Perihematoma Brain After ICH And The Neuroprotective Effect Of Rhubarb For ICH

Background and Purpose——Itracerebral hemorrhage represents at least 10%of all strokes.The prognosis of patients after ICH is poor,and mortality rates approach 58% with high levels of residual disability.The pathophysiology of damage after ICH remains poorly understood,Recent studies have shown that perihematomal mitochondrial respiration function degraded in intracerebral hemorrhage(ICH) patients and cytochrome c immunoreactivity increased in perihematoma of Spargue-Dawley rats.The first purpose of this study is to examine the ultrastructural changes of neuronal mitochondria in perihematoma brain after ICH.Rhubarb is a drug with good clinical prospects,which has broadly neuroprotective effects by attenuating mitochondrial dysfunction.The second purpose of this investigation is to test the neuroprotective effects of rhubarb for ICH as well as its mechanism.Method——ICH was produced in adult Spargue-Dawley rats by injection of collagenaseⅣ(0.05U/0.5uL).The animals' brains were removed at 3,6,12,24or 48 hours after hemorrhage,and fixed tissue was prepared for electron microscopic examination.Neurons around hematoma were photographed randomly and perinuclear mitochondria were analyzed in a blinded manner for qualitative ultrastructural changes(compared with sham control) by independent investigators. TUNEL stained cells were assessed in perihematoma region.Intraperitoneal injection of rhubarb(Sml/kg) or saline,was started at 3,6 or 12 hours post-ICH.Casepase-3 activity,TUNEL and neurological behavior function were performed 24hours after ICH.Results——1.Mitochondria in perihematoma neurons appeared obvious morphological changes,including mitochondrial swelling,intracristal dilation and increased electron density of the matrix.2.The changes mentioned above started at as early as 6 hours after surgery,and abnormal mitochondria were predominent at about 12,24,48 hours after ICH.3.There were a lot of apoptosis cells around hematoma, which peeked at 24 hours after ICH(P＜0.05).4.Rhubarb given at 3 or 6 hours can inhibit casepase-3 activity(P＜0.001),reduce TUNEL positive cells(P＜0.05) and attenuate apomorphine-induced rotation(P＜0.05) at 24 hours after ICH.However, the animals which were treated 12 hours showed no improvement. Conclusions——1.Intracerebral hemorrhage leads to mitochondrial damages in acute period.2.TUNEL positive cells peeked at 24 hours after ICH.3.Rhubarb may be a potential drug for ICH patients for its possible effect of inhibiting apoptosis that depents on mitochondrial dysfunction.This may suggest a new direction for therapeutic interventions for ICH.