| Objective:The purpose of the study was to investigate the effect of the topical application of Tacrolimus (FK506) on preventing epidural adhesion after laminectomy surgery.Method:72healthy SD rats were used in the experiment and equally divided into four groups: O.lmg/ml group,0.05mg/ml group,0.01mg/ml group and saline control group,18rats in each group. Laminectomy was performed at Lumbar-1level in each animal and different concentrations of FK506and saline were applied to the laminectomy sites for5min after hemostasis. The muscle and skin were sewed in layers with non-absorbable silk after irrigating with saline solution. BBB scoring was applied for all the animals before and after the surgery in order to detect the primary safety. Four weeks later the rats were killed and the epidural adhesion was evaluated. Macroscopic assessment, hydroxyproline content of the scar tissue, histological analysis, fibroblast counting and mRNA measurements of the scar tissue were used to evaluate the effect of FK506on preventing epidural scar adhesion. Sum Rank Test and ANOVA were applied to analysis the date. P<0.05was considered statistically significant in all analysis.Result:All the animals in the experiment achieved good recovery. There is no mortality and no sign of wound infection.(1) BBB scoring were both21before and after the experiment showed that there is no sign of spinal cord injury.(2) Macroscopic assessment was used after four weeks. Macroscopic assessment showed that soft or weak fibrous adhesion was seen in the laminectomy sites in0.1mg/ml FK506group. Moderate scar adhesion was found in the laminectomy sites in0.05mg/ml FK506group, which could be dissected by manual traction with less bleeding. However, severe epidural adhesions were observed around the laminectomy sites in O.Olmg/ml FK506group and control group, which were difficult to dissect the scar adhesions accompanied with bleeding and disruption of the dura mater.(3) The HPC in0.1mg/ml FK506group and0.05mg/ml FK506group were less than that in control group (P<0.05), the content in0.01mg/ml FK506group showed no significant difference compared with that of control group (P>0.05), but the content in0.1mg/ml FK506group was less than that of in control group (P<0.05).(4) In 0.01mg/ml FK506group and control group, dense epidural scar tissue with widespread adhesions to dura mater and dorsal muscle were observed in the laminectomy sites. A large quantity of fibroblasts appeared in the scar tissue around the laminectomy sites. In0.05mg/ml FK506group, moderate epidural scar adhesion was observed and fibroblasts were decreased in the scar tissue compared with those of control group. However, loose or little scar adhesion was observed in the laminectomy sites in0.1mg/ml FK506group and the number of fibroblasts was significantly less than those of0.05mg/ml,0.01mg/ml FK506group and control group.(5) The fibroblast number in0.1mg/ml FK506group and0.05mg/ml FK506group were less than that in control group (P<0.05), the fibroblast number in0.01mg/ml FK506group showed no significant difference compared with that of control group (P>0.05), but the fibroblast number in0.1mg/ml FK506group was less than that of in control group (P<0.05).(6) The mRNA expressions of IL-4in O.lmg/ml FK506group,0.05mg/ml FK506group O.Olmg/ml FK506group were lower than that of control group (P<0.05). The mRNA expression of IL-4in O.lmg/ml FK506group was also lower than that of0.05mg/ml FK506group (P<0.05); The mRNA expression levels of TGF-P in O.lmg/ml FK506group,0.05mg/ml FK506group0.01mg/ml FK506group were lower than that of control group (P<0.05). The mRNA expression of TGF-β in0.1mg/ml FK506group was also lower than that of0.05mg/ml FK506group (P<0.05).Conclusion:The results showed that topical application of FK506could inhibit the expression of IL-4and TGF-β, fibroblast proliferation and prevent epidural scar adhesion after laminectomy with a dose-dependent manner. Moreover, O.lmg/ml FK506had a better preventive effect than any other concentration. |
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