The Effect Of Cholecystokinin Octapepide On Paw Withdraw Thermal Latency Of Arsenic-poisoning Rat

Part 1. The effect of cholecystokinin octapeptide on paw withdraw thermal latency of arsenic-poisoning rat.Objective: The study on the effects of arsenic poisoning on body weight and parts of indexes of biochemistry in rats. To investigate effects arsenic poisoning in rats and CCK on PWTL in arsenic poisoning rats .Methods:To investigate these effects, 48 female Wistar rats were randomly diveded into notmal saling(A)group, arsenic poisoning(B,C and D)group,(16 rats in A and B group, 8 rats in C and D group, group A inject 0. 9 % sodium chloride at 1ml /100g for seven days, group B,C and D given NaAsO2 injection for seven days. The NaAsO2 injection and 0. 9 % sodium chloride of group A were injected via caudal vein. The body weight of group A and B were measured before injection and after fifteenth day of injection. Half of group A and B were decapitation to obtain their blood at the eighth day to measure parts of indexes of biochemistry. At the eighth day, group C were injected CCK-8S at 0.05 mg/kg via subcutaneous,group D received 0. 9 % sodium chloride via subcutaneous, and record their PWTL, To investigate the effect of cholecystokinin octapeptide on PWTL of arsenic-poisoning rat. Results: There were significant statistical difference between the weight of group B and group A. There were significant statistical difference between the ALT,TP,BU and Cr of group A and group B. The ALT and TP in F group were distinctly lower than E group, the BU and Cr were distinctly greater than E group. Before experiment there was no significant difference in PWTL between group A and group B, after 8 days there is significant difference in PWTL between group A and group B. After CCK-8S injection there was significant prolong in PWTL in group C between 15 min and 60 min compared to before injection and group D.Conclusions: The weight of the arsenic poisoning rats decreased distinctly and parts of indexes of biochemistry changed significantly. This study shows that CCK-8S significant reduces the thermal hyperalgesia of arsenic–poisoning rat CCK-8S have analgesic effect to arsenic -poisoning rat. Part 2. The study on the morphology of dorsal root ganglion,spinal cord and thalamic of arsenic-poisoning rat.Objective: To observe the histopathologic and ultrastructure change of dorsal root ganglion,spinal cord and thalamic of arsenic-poisoning rat to study pathological mechanism of sensory dysfunction of arsenic-poisoning.Methods:To investigate these effects, 16 female Wistar rats were randomly diveded into notmal saling(A)group, arsenic poisoning(B) roup(8 rats in each group), roup A inject 0. 9 % sodium chloride at 1ml /100g for seven days, group B received NaAsO2 injection for seven days. The NaAsO2 injection and 0. 9 % sodium chloride of group A were injected via caudal vein. At the eighth day, All rats were deeply anaesthetized with 20% Urethene and perfused transcardially with 150 ml saline followed 300 ml cold (4℃)fixative solutions containing 4% paraformaldehyde and glutaradehyde. Thalamus, spinal cord and corresponding DRG were removed and cut into ultrathin section for observation. Results:In the DRG vascular dilatation and hyperaemia, the necrotic of neurons and inflammatory cell infiltration, some DRG neurons suffered neuronophages, the number of small ganglionic cells reduced, vacuolar degeneration, the neis body were light stained was seen under a light microscope, primary lysosome were increased significantly and mitochondrial degeneration were seen under electron microscope. In the dorsal horn, the number of small cells and the number of small ganglionic cells reduced,perivasculitis,neuronophagia in pathology were were observed by light microscope. Under a transmissiion electron microscope, neuron pyknosis, the volume of nucleus was diminished, chromatin margination, dispersion of nucleolus, the myelinoclasis of myelinated nerve fibers, the membranes of pre-synaptic and post-synaptic were not clear and synaptic cleft disappeared, and severe damage of mitochondria of synapse were seen under a transmission electron microscope. The volume of neuron was significantly reduced, neuron pyknosis, cytoplasm decreased, the number of organells decreased, chromatin margination, dispersion of nucleolus, some thalamic neurons suffered neuronophages by glial cells were seen Under a transmissiion electron microscope.Conclusions: DRG, spinal cord and thalamus have found severe lesion in this subacute toxic mode1,and this can be the pathological basis of the sensory dysfunction in this model.