Hindlimb dysfunction character in response to spinal cord ischemia/reperfusion in rabbits / 中华创伤杂志

ABSTRACT

Objective To investigate the effect of spinal cord ischemia/reperfusion injury on hindlimb dysfunction in rabbits.Methods Twenty-eight health adult rabbits were distributed into normal control group (n =4) and model group (n =24) according to the random number table.The modelof spinal cord ischemia/reperfusion injury was established by selective occlusion of lumbar arteries.The model group were submitted to ischemia for 30 min (Group Ⅰ),60 min (Group Ⅱ) and 90 min (Group Ⅲ) before the reperfusion with 8 rabbits each.Jacobs score,Reuters score and Rivlin inclined plane test were used to evaluate the hindlimb function in each Group at days 1,3 and 7 after reperfusion.Changes in nerve conduction function in each group were observed using the cortical somatosensory evoked potential (CSEP).Results At days 1,3 and 7,the paraplegia rates in group Ⅰ were 50％,38％ and 38％ respectively,in Group Ⅱ were 75％,88％ and 100％,and in Group Ⅲ were all 100％.Paraplegia rate differed significantly among the three groups at 1 d and 3 d (P ＜ 0.01).Paraplegia rate differed significantly in Groups Ⅱ and Ⅲ when compared to that in Group Ⅰ at 7 d (P ＜ 0.01),but there was no significant difference between Groups Ⅱ and Ⅲ (P ＞ 0.05).With the prolongation of reperfusion,the Reuters score in Group Ⅰ dropped but not differed from that in control group (P ＞ 0.05);the Reuters score in Groups Ⅱ and Ⅲ increased and differed from that the control group (P ＜0.01),but the difference between Groups Ⅱ and Ⅲ was insignificant (P ＞ 0.05).Critical angle and obstacle rate of the inclined plane in control group were (68.4 ± 3.0)° and 0％.One day after reperfusion,critical angles of the inclined plane in Groups Ⅰ,Ⅱ and Ⅲ were (58.8 ± 4.1) °,(38.5 ± 2.8) ° and (29.8 ± 1.8) °,and the obstacle rates were (14.5 ± 0.9) ％,(43.6 ± 2.4) ％ and (56.0 ± 2.9) ％.There were significant differences compared to control group (P ＜ 0.01).Slight decrease in critical angle of the inclined plane but a minor increase in the obstacle rate was detected in Groups Ⅱ and Ⅲ at 3 d and 7 d after reperfusion,and the differences were significant compared to control group (P ＜ 0.01).Three days after reperfusion,critical angle of the inclined plane raised and obstacle rate of the inclined plate fell in group Ⅰ,not significantly different from these in control group (P ＞ 0.05).Latencies of CSEP N1 and P1 waves in Group Ⅱ [(33.1 ± 1.8) ms and (58.6 ± 4.0) ms] were longer than these in control group [(23.7±0.5)msand (48.1±4.1)ms]andgroup Ⅰ [(26.2±0.7)ms and (50.2±4.2)ms] (P＜ 0.01) 7 days after reperfusion,but the differences between control group and Group Ⅰ were insignificant (P ＞ 0.05).While the CSEP wave disappeared in Group Ⅲ.Conclusions Severity of spinal cord inschemia/reperfusion injury is related to the duration of ischemia.Hindlimb dysfunction caused by ischemia/reperfusion injury is characterized mainly by spastic paraplegia.