低能激光照射对大鼠梗死心肌保护性细胞因子的影响

Effect of low level laser irradiation on protective cytokines in infarcted myocardial tissues of rats

目的观察不同能量密度低能激光照射（LLLI）对大鼠梗死区心肌保护性细胞因子：内皮生长因子（VEGF）、诱导型一氧化氮合酶（iNOS）、葡萄糖调节蛋白78（GRP78）的影响。方法开胸直视下结扎冠状动脉制作SD大鼠心肌梗死模型。3周后经胸心脏彩超筛选符合入组条件的大鼠，随机分为：对照组：仅开胸不进行低能激光照射（n=20）；低能激光照射：二极管激光治疗仪，波长635nm，输出功率6mW，据不同能量密度分为：0．32J／cm。（A组n=20）、0．64J／cm^2（B组n=20）、0．96J／cm^2（c组n=20）、1．28J／cm^2（D组n=20）、1．60J／cm^2（E组n=20）。LLu处理后48h采集梗死心肌标本，以Westernblot法测定VEGF、iNOS的表达；以反转录一聚合酶链反应（RT-PCR）法检测GRP78的表达。结果A、B、C、D、E组VEGF、iNOS、GRP78水平[（23．7±3．5）、（9．7±2．8）、（15．4±2．3）pg／μg蛋白；（35．4±4．0）、（21．6±3．6）、（19．7±1．9）pg／μg蛋白；（45．1±5．9）、（42．6±3．8）、（31．4±2．4）pg／μg蛋白；（44．7±2．7）、（40．8±2．9）、（31．1±1．7）pg／μg蛋白；（44．5±5．7）、（40．1±2．6）、（30．8±3．1）pg／μg蛋白]与对照组[（14．2±4．1）、（5．2±1．7）、（8．1±2．1）pg／μg蛋白]比较明显升高（P均=0．000）。与A组比较，B组VEGF、iNOS、GRP78表达水平明显升高（P=0．025、0．013、0．006）。与B组比较，C组VEGF、iNOS、GRP78表达水平明显升高（P=0．004、0．031、0．015）。与C组比较，D组VEGF、iNOS、GRP78表达水平差异无统计学意义（P=0．843、0．248、0．391）。与D组比较，E组VEGF、iNOS、GRP78表达水平差异无统计学意义（P=0．516、0．410、0．736）。结论0．96J／cm^2的能量密度为LLLI治疗大鼠急性心肌梗死的最佳能量密度。

Objective To investigate the effect of low level laser irradiation （LLLI） with different energy density on protective cytokines： vascular endothelial growth factor （VEGF） , inducible nitric oxide synthase （iNOS） and glucose regulated protein 78 （GRP78） in infarcted myocardial tissues of rats. Methods The model of SD rat myocardial infarction was established by ligating coronary artery under thora- cotomy. 3 weeks later, the rats which were underdone transthoraeic echocardiography were randomly divided into six groups： the control group and rheA, B, C, D, E group. The control group received coronary artery ligation but no laser irradiation（n =20）. The other five groups received LLLI （635 nm, 6 mW diode laser） with the irradiation energy density individually is 0. 32 J/cm2 （A group n =20）, 0. 64 J/cm2 （B group n = 20）, O. 96 J/cm^2 （ C group n = 20）, 1.28 J/cm2 （ D group n = 20）, 1.60 J/cm2 （ E group n= 20 ）. The infarcted myoeardia were excised at 48 h after LLLI. The expressions of VEGF and iNOS were measured by Western blotting, and the expression of GRP78 was measured by the reverse transcriptase -polymerase chain reaction （RT- PCR）. Results The expressions of VEGF, iNOS and GRF78 in the A, B, C, D, E group [（23.7±3.5）, （9.7±2.8）, （15.4±2.3）pg/μg protein; （35.4±4.0）, （21.6±3.6）, （19.7± 1.9） pg/μg protein; （45. 1±5.9）, （42.6±3.8）, （31.4±2.4） pg/μg protein; （44.7±2.7）, （40.8±2. 9）, （31.1 ± 1.7） pg/μg protein; （44. 5 ±5.7）, （40. 1±2. 6）, （30. 8 ±3. 1） pg/μg protein] were sig- nificantly higher than that in the control group E （ 14. 2 ± 4. 1 ）, （5. 2 ± 1.7）, （ 8. 1± 2. 1 ） pg/μg protein ]（P = 0. 000）. The expressions of VEGF, iNOS and GRP78 in the B group was significantly higher than that in the A group （P =0. 025, 0. 013, 0. 006）. The expressions of VEGF, iNOS and GRP78 in the C group was significantly higher than that in the B group （P =0. 004, 0. 031, 0. 015 ）. The expressions of VEGF, iNOS and GRP78 in the D group have no significant difference with the C group （P = 0. 843, 0. 248, 0. 391 ）. The expressions of VEGF, iNOS and GRP78 in the E group have no significant difference with the D group （P =0. 843, 0. 248, 0. 391）. Conclusion The best LLL1 energy density is 0. 96J/cm2 in the treat- ment of rats acute myocardial infarction.