| Backgrounds With the increasing acquaintance of the soluble gas signaling transmitter Nitrogen Monoxide(NO) in biological and pathological conditions,another gas transmitter Carbon Monoxide(CO) is now drawing more and more attentions. Endogenous CO is one of the byproducts of Heme Oxygenase(HO). The HO existing widely in liver,spleen,brain,endothelium of vessel and other tissue and organs. It has been confirmed that Nitrogen Monoxide-Nitrogen Monoxide Synthase system acts as an cellular-toxic-factor in secondary spinal cord injuries,what role does Carbon Monoxide-Heme Oxygenase plays in SCI is an unknown while intriguing question. In this study we will explore the substantial functions of HO by determine the expression and translation of HO gene in spinal cord of normal and CO-PP induced rats,and evaluate motor and sensation functions post spinal cord injuries in normal and HO inhibited rats. Objectives:1. To detect two types of hemeoxygenases (HO) in rat spinal cord both in mRNA expressions and protein level. 2. To investigate the gene expression and translation of two types of heme oxygenase in injured spinal cord. 3.Methods:1. Total RNA were extracted from normal and Cobalt -Protoporphyrin treated SD rat's spinal cord by the guanidine isothiocyanate/cesium chloride method and Poly (A+) RNA was isolated by oligo (dT)-cellulose chromatography and analyzed by Northern Blot. Coffin embedded slides of rat's spinal cords were detected by immunohistochemistry method.2. Forty-eight mail SD rats,weight 220 to 290g,were randomly divided into six groups:Noninjured,2hr,6hr,12hr,24hr,48hr post spinal cord injury. Eight in each group. The rats in injury groups underwent 35gX Sminutes compression on T12-L1 levels. The rats were killed in corresponding time periods post spinal cord injury and spinal cord were adopted six for RT/PCR,two for immunohistochemistry.3.Twenty rats,half male and half female were coupled according to their gender and weight,and divided into two A and B groups. Each rat underwent a 35gX5min compression on their T11-L1 spinal cord. But group A received an introdural injection of Zn-PP(200 u 1,500nM) 10 minutes before injury. And followed by introventricle injection of same drug in the next 3 days. Group B received injections of equal volume of saline in the same manner. Capacity angle were determined 1,2,3,4,5,7,14,21days after injury. Cerebral Somatosensary Evoked Potentials(CSEP) of tibia nerves were estimated in 7 and 21 days after injury. MRI of the Spines were examined 21 days after injury.Results:!.HO-1 probe detected 1.8-kb mRNA in all samples,and the message in CoPP treated rats were increased by fords. Blot hybridization with HO-2 probe revealed the presence of two homologous transcripts (1.3 and 1.9-kb) in all samples with relatively equal abundance. Immunohistochemistry reveal the HO-1 mainly distributes in anterior horn,and it is also found in middle region in induced rat. HO-2 positive cells scatter in the whole Gray Matter.2. In normal groups,two types of HO were detected,type 1 has relatively better abundance.HO-1 immunoreactive neurons mainly located in anterior horn while HO-2 immunoreactive neurons scattered in the wholegray matter. As for injured groups,HO-1 mRNA were detected in all groupes and have better abundance compared with noninjured rats,especially in 2,4,6,12hr after injury. Expression of HO-2 were also increased especially in 6,12hr after injury. HO-1 protein were detected by immunohistochemistry 24hr after injury and distributed all of the gray matter. Number of HO-2immunoreactive neurons were also increased after SCI.3. The average Capacity angle of group B recovered to 63.4 in 21 days after injury in contrast with that of group A only 45.9 (P<0.01)0 Average latency of CSEP in Group B(14.34ms) is shorter than that in group A(18.12ms)(P<0.01),while amplitude(20.39 U V) is higher than that in group A(15.58u V)(P<0.05). MRI of B group reveal relatively normal results in compare with that in group A which often show narrowed spinal cord and a...
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