The Critical Role Of Lysyl Oxidase(LOX) In Chronic Compression Of Rat Spinal Cord

Objectives This experiment replicates chronic spinal cord injury model by method of progressive screw. By comparing the difference between lysyl oxidase promotion group 、lysyl oxidase inhibition group 、positive control group and negative control group, to investigated the function of lysyl oxidase in spinal cord under chronic compression. The change of CSEP、HE staining、IHC in different groups were observed so as to offer theoretical evidence for supporting intervention measure.Methods Adult female Sprague-Dawley rats(250-300g) were randomly divided into 4 groups: normal group(group A,n=15);positive control group(group B, n=15); compression +BAPN, LOX inhibition group(group C,n=15);compression +Cocl2, LOX promotion group(group D,n=15). After screw were set in spinal, group B: regular water and food; group C:BAPN 1g/KG(intraperitoneal injection daily); group D: Cocl2 30mg/L(drinking water).Keep Culturing 8weeks, during this progress BBB score、Tarlov score were observed and CSEP measured as plan. And then harvested spinal cord tissue for HE、IHC、RT-PCR.Results The spinal cord RT-PCR shows that comparing with control group all the injury groups’ lysyl oxidasel expression were increased in different level. The increasing in group D was the most obvious, it means Cocl2 enhanced the expression of lysyl oxidasel in spinal cord. In contrast the increasing in group C was mild, it means BAPN inhibited the expression of lysyl oxidasel. According the result of CSEP, except group A the other groups’ latency were increased. The difference among the compression groups showed up at week 6 and then at week 8 significant. At week 8 LOX promotion group D CSEP(18.06±0.67)ms,positive control group B CSEP(19.76±0.82)ms, LOX inhibited group C CSEP(22.16±0.74)ms. After analysis the HE staining sections, comparing with LOX inhibition group, there are many vacuoles surrounding axon and more edema disorder structure,the number of neuron decreased. In grey matter neuron pyknoses obvious Nissl body were rare observed. According IHC to check the expression of Bcl-2/Bax and then to observe the apoptosis of spinal cord neuron. The expression of Bcl-2 in different groups:the average optical density in control group A was(0.48±0.01),positive control group B was(0.36±0.02), LOX inhibited group C was(0.25±0.02), LOX promotion group D was(0.31±0.01). The expression of Bax in control group A was lowest. The other groups’ Bax level higher than group A,and this kind of increasing was most obvious in group C. Comparing with group C, the expression of Bax in group D decrease and significant(P<0.05).Conclusions Lysyl oxidase acted as an important role during the chronic compression of spinal cord.