The Effect Of Hemorrhage On Neural Behavior And Cell Apoptosis In The Hippocampus CA1 Zone Of The Rats Under Controlled Hypotension

Objective: To observe the effect of hemorrhage on neural behavior and cell apoptosis in the hippocampus CA1 zone of the rats under controlled hypotension (CH) .To explore the tolerance capability of hemorrhage in rats under CH.Methods: 56 SD rats were randomly divided into 2 groups:C group(with no controlled hypotension) and H group(with controlled hypotension),esch group set four level ratio of blood loss to total blood volume:C1,H1group(10%),C2,H2 group(20%), C3,H3 group(30%) and C4,H4 group(40%).Each group contain 6 SD rats. In H group CH was achieved by sodium nitroprusside(SNP) and esmolol(ESM) to mean arterial pressure (MAP) level of 50～55 mmHg and maintaining for 10 minutes, then rats was to loss blood through femoral artery,keeping the pumping speed of this time. In C group rats was keeping pump normal sodium with no CH and had the same style of hemorrhage. Boost pressure after lasting for 60 minutes after hemorrhage. To record vital sign of rats and aterial blood gas analysis during the course. To observe the open field test and inclined plane test of surviving rats,to detect the expression of bcl-2 and caspase-3 using immunohistochemical method and apoptosis cells using TUNEL method in hippocampus CA1 zone, to calculate the survival rate after 24 hours.Results: Survival rate after 24 hours were respectively : 100%, 100%,100%,50% for C group,100%,100%,83%,17% for H group,there is statistical defferences between group H4 and group H1,H2,H3 (P<0.05).There is no differences observed among groups of the open field test and inclined plane test(P>0.05). Average optical density of bcl-2 in group H3 were higher than group C3(P<0.01),H1 and H2(P<0.05). Average optical density of caspase-3 in group H3 were higher than group C3,H1 and H2(P<0.05). Apoptosis index in group H3 were higher than other group(P<0.05).Conclusions:1. Losing 30% blood under CH induced by SNP and ESM made higher expression of bcl-2,caspase-3 and more apoptosis cells than lose the same volume blood simply,but it is not the same when blood loss volume was 10% and 20% in rats. Losing 10%,20%,30% blood simply do not induce cerebral ischemia in rats.2. There is no difference on the neural behavior at 24 hours after hemorrhage for different degree under CH induced by SNP and ESM in rats.3. Rats cannot tolerate losing 40% blood volume under CH induced by SNP and ESM,for their low survival rate.