Research Of Magnetic Liposomes Crossing Blood Spinal Cord Barrier After Spinal Cord Injury In Rats

This research will evaluate the security and biocompatibility of magnetic liposomes administrated intravenously.It will also evaluate the ability of this kind of novel liposomes modified with polyethylene glycol(PEG) and transactivating-transduction protein(TAT) to cross the blood spinal cord barrier(BSCB) and finally demonstrate whether they can accumulate at the lesion of injured spinal cord.1. The novel magnetic liposomes was prepared with diffierent concentration. Forty-eight Wistar rats were divided into four group randomly:the high concentration group wih 7.5mg/ml,moderate concentration group with 3.25mg/ml, lower concentrations group with 1.625mg/ml and control group with normal saline.The rats in diffierent group were injected with the magnetic liposomes through the caudal vein.Within 7d after injection the security was evaluated by general situation in rats and through HE,Prussian blue staining.2. Thirty-six Wistar rats were subjected to spinal cord injury(SCI) at T10,then divided into three groups randomly(groupA,groupB and control group).The rats of groupB were injected with TAT-PEG loaded magnetic liposomes(4.55mg/kg) that could cross the BSCB through the caudal vein.The rats of groupA the were injected with the equivalent PEG loaded magnetic liposomes while control group with the equivalent normal saline.The accumulation of nanoparticles was observed by MRI,Prussian blue staining,electron microscope and flame atomic absorption spectrophotometer.1. The rats'general situation in experiment group was the same as in control group and there are not any significant diffierents in histochemical staining besides a small amount of Prussia blue staining positive granules in liver in high concentration group.2. It can be found from the results that this kind of magnetic liposomes can cross the BSCB and gather into the cells around the injured tissue.Low signal in T2WI of MRI can also be found. The result of flame atomic absorption spectrophotometer showed that the iron content accumulating around the lesion site in groupB is obviously higher than the other two groups(p<0.05).1. This kind of magnetic liposomes was relatively safe administrated through caudal vein especially with a concentration below 7.5mg/ml(100mg/kg).2. This TAT-PEG loaded magnetic liposome as a kind of novel drug carrier can cross the BSCB and accumulated at the tissue of the spinal cord. We believe that these TAT-PEG loaded magnetic liposomes can be regarded as a new strategy for the treatment of spinal cord injury.