L-精氨酸对创伤性面瘫大鼠面神经NOS表达的影响

Effects of L-arginine on the expression of nitric oxide synthase in facial nerve in traumatic facial paralysis rats

目的 :研究一氧化氮前体L 精氨酸 (L Arg)与组成型一氧化氮合酶 (cNOS)抑制剂L 硝基精氨酸对创伤性面瘫大鼠外周面神经及周围组织一氧化氮合酶 (NOS)表达的影响。方法 :通过大鼠面瘫前后腹膜内给予L 精氨酸与L 硝基精氨酸 ,在伤后各个时间点上切取损伤面神经和软组织 ,并采用免疫组织化学ABC法对面神经和肌肉软组织内NOS表达的变化进行研究。结果 :L 精氨酸组面神经损伤后有cNOS表达 ,2组肌肉伤后呈现一定程度的cNOS、iNOS(诱导型一氧化氮合酶 )免疫反应性 ,且反应相似。结论 :L 精氨酸组面神经损伤后有cNOS表达 ,可能促进神经再生 ;而iNOS表达则阻碍神经再生。

Objective :To study the effects of NO precursor, L-arginine(L-Arg) and constitutive nitric oxide synthase(cNOS) inhibitor, L-nitroarginine(L-NNA)) on the expression of cNOS in facial nerve and surrounding tissues in traumatic facial paralysis rats. Methods:Facial paralysis was surgicaly created by impact in 57 SD rats. The rats were divided into 3 groups with 18 in each group, another 3 rats were used for morphological study. L-Arg at 40 mg/kg or L-NNA at 50 mg/kg were intraperitoneally injected into rats 2 times a day, from 4 days before untill 14 days after surgery(group L-Arg and group L-NNA). In control group(NS) same volume of normal saline was given to the rats after creation of facial paralysis. The facial nerve and surrounding tissue samples were obtained at different time. Immunohistochemical ABC method was used to examine cNOS and inducible NOS (iNOS) expression in facial nerve and surrounding tissues. Results:cNOS immunoreactivity was observed in traumatic facial nerve in L-Arg group 7 days after trauma and in the adjacent muscle in the 3 groups from 6 h to 3 d after trauma. iNOS was found in the paralyzed nerves from 1 d to 7 d after trauma in the 3 groups, and in the adjacent tissues from 6 h to 3 d after trauma in the 3 groups. Conclusions:L-Arg may stimulate constitutive NOS expression in facial nerve and probably promote the nerve regeneration.