Light Response Neurotoxin Nanocapsule Preparation And Its Analgesic Mechanism

Neurotoxin isolated from snake venom has central analgesic activities. Different kinds of neurotoxin have different mechanism. What’s more, neurotoxin can not pass through blood brain barrier, which leads to poor central analgesic effect.In this experiment, neurotoxin was obtained by separation and purification form crude venom of Chinese cobra breed in Jiangxi, and it’s central analgesic mechanism and pharmaceutical preparations were studied further. The main research methods and results were as followed:(1) Crude venom was isolated by eluent through CM-agarose gel CL-6B cation exchange column and Sephadex G-50 gel filtration chromatography column alternately. At the same time, the target product was tracked by HPLC method to obtain high purity of neurotoxin. In final, the total extraction yield of neurotoxin was about 9.5%. This operation process was simple and reproducible.(2) The rational possible molecular mechanism of pain treated with neurotoxin was studied by spinal cord injury model. This experiment used kits to detect content changes of the relevant signaling molecules and used antibody to verify its receptor pathway hypothesis by Western bloting method. The results showed that ATP content, ROS content and the expression of MAPK ERK1/2 enzyme levels in brain tissue had obvious changes, which showed that cobra neurotoxin may have effects on expression of certain enzymes in the pathway or signal molecules. Combined with previous research results, cobra neurotoxin may play analgesic mechanism in a certain degree along with adenosine receptor pathway.(3) This experiment explored optimal factors to prepare light response micro nanometer capsule and liposomes by lysozyme as model drug. Light response neurotoxin PLGA and PEG-PLGA nanocapsule were prepared and characterized. The results showed that their envelopment rates were 25.1% and 22.3%, drug loading were 3.30% and 3.09% respectively and particle size was 800 ~ 1200 nm. In vitro experiments, the release curve of light response lysozyme had better performance of optically controlled release at 650 nm. In addition, light response neurotoxin liposome was also prepared and characterized. The results showed that its encapsulation rate was 25.5%, drug loading was 3.8%, the particle size was 225.59±0.49 nm, and the potential was 53.50±3.25 mV. The liposomes using this preparation method showed good reproducibility and stability. In analgesic experiments by hot plate method, compared with the analgesic effect of active pharmaceutical ingredients, this light response liposome showed good optically controlled release of drugs, and improved analgesic effects to a certain extent.In this paper, the adenosine receptors mechanism of neurotoxin was proposed and the light controlled release of red light response of neurotoxin nano preparation was realized.