The Effect Of Botulinum Toxin Serotype A Heavy Chain On General Protein Expression Pattern,Myelin-associated Glycoprotein And Its Receptor After Spinal Cord Injury In Rats

Objective:1.To observe the effect of botulinum neurotoxin type A heavy chain(BoNT/ A HC)on the general expression pattern of spinal protein expression after spinal cord injury in rats;2.To explore the intervening role of BoNT/A HC in the expression of myelin associated glycoprotein(MAG)and its specific membranous receptor(Nogo-receptor,NgR).The purpose of the study is to provide some experimental evidence for elucidating the mechanism of BoNT/A heavy chain to stimulating neurite outgrowth.Methods:1.The model of unilateral lumbar spinal cord injury(SCI)was established using modified needle of 1ml syringe.BoNT/A HC was intraspinally given at the same time by injection through micro-syringe.Doses of 2?g,4?g,6?g and 8?g of BoNT/A HC were chosen respectively;2.For detecting the general pattern of protein expression in the spinal cord tissues at the injury site,including the injury center and 2~3cm cranial part which is just adjacent to the injury center,was investigated by SDS-PAGE and Coomassie brilliant blue staining first,and then by two-dimensional gel plus silver nitrate staining;3.The expression of both MAG and NgR at the above location were examined using western blot.Results:1.The model of spinal cord injury displayed obvious destruction and degradation of ipsilateral gray and white matter;2.Coomassie brilliant blue staining to SDS-PAGE gel showed the bands of general protein expression were dramatically latered in SCI only group compared with controls.Some bands were decreased,some increased.Interestingly,the bands of protein patterns after BoNT/A HC application appeared quite different from SCI only group,but similar to the outlook of controls somewhere.Meanwhile,the result from two-dimensional gels stained by silver nitrate indicated that the alteration of protein general expression pattern after BoNT/A HC was involved in a quite few of areas with different molecular weight and isoelectronic points.Many of dots and dot-groups on gels appeared different with/without BoNT/A HC treatment,compared to those in controls.Summarily,the general protein expression after BoNT/A HC showed the tendency toward the pattern similar to control;3.BoNT/A HC reduced the expression of MAG and NgR which were highly upregulated after SCI.Conclusions:1.Localized application of BoNT/A HC at the injury site of SCI affects the general pattern of protein expression after SCI;2.BoNT/A HC reversed the protein expression which was altered after SCI toward the similar to those in controls;3.BoNT/A HC reduce the expression of MAG and NgR.