肌红蛋白基因多态性与运动性肌肉损伤的相关性

 目的 探讨肌红蛋白（myoglobin, Mb）基因第2外显子单核苷酸多态（A79G）与运动性肌肉损伤的关系。方法 85名武警战士进行一次大强度负重运动，检测血清肌酸激酶（creatine kinase，CK）活性的时程变化；聚合酶链反应-限制性片段长度多态（PCR-RFLP）法测定Mb基因多态性；分析基因多态性与安静CK（CK_pre）、峰值CK（CK_peak）及CK最大变化值（△CK）的关系。结果 CK_pre为（145±33）U/L，大强度运动后24 h开始逐渐升高，72 h达峰值［CK_peak：（2972±1648）］U/L，随后缓慢下降，120 h仍高于安静水平。3种基因型的分布频率分别为AA（54.1%）、AG（40.0%）、GG（5.9%），等位基因分布频率为A（74.1%）、G（25.9%），符合Hardy-Weinberg遗传平衡定律。组间比较，（AG+GG）组CK_pre、CK_peak和△CK均高于AA组（均P＜0.01）。结论 运动性肌肉损伤易感性与Mb基因第2外显子单核苷酸多态（A79G）有关，G等位基因具有肌肉损伤易感性，而AA基因型则具有运动性肌肉损伤保护作用。

Relationship between myoglobin gene polymorphism and exercise-induced muscle damage

Objective To study the relationship between single nucleotide polymorphism (A79G) and (T109C) in the second exon of the myoglobin gene and exercise-induced muscle damage. Methods Eighty-five soldiers of CAPF performed a strenuous weight-loading exercise and the time course of serum creatine kinase (CK) activity was measured. Myoglobin gene polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Association between resting CK (CK_pre), maximal CK (CK_peak), maxiaml changes in CK (△CK) and gene polymorphism was then analysed. Results The activity of CK ［CK_pre: (145±33) U/L］ gradually increased at 24 h after strenuous exercise and reached peak value at 72 h［CK_peak: (2972±1648) U/L］, which then slowly reduced, but still higher than rest level at 120 h. The genotype frequencies (AA=54.1%, AG=40.0%, GG=5.9%) and allele frequencies (A=74.1%, G=25.9%) were coincident with Hardy-Weinberg equilibrium. Compared between groups, CKpre, CKpeak and △CK in (AG+GG)-group were all higher than those in AA genotype group (all P＜0.01). Conclusions The single nucleotide polymorphism (A79G) in the second exon of the myoglobin gene might contribute to susceptivity of exercise-induced muscle damage. Subjects with G allele have increased risk for developing muscle damage, whereas AA genotype may have protective effects.