目的：探讨硫辛酸烟酸二联体(N2L)对蓝光致SD大鼠视网膜损伤的防治作用及最佳药物剂量，探寻其可能存在的保护机制。

方法：选取150-200 g的SPF级雄性SD大鼠36只，随机分为正常对照组、蓝光损伤组、N2L低剂量组(1.0 mg/kg)、N2L中剂量组(2.5 mg/kg)、N2L高剂量组(5.0 mg/kg)及生理盐水组，每组各6只。正常对照组12 h明暗循环饲养，其余组每日接受9 h日常光照，3 h波长455 nm、强度3000±50 lx蓝光照射及12 h黑夜来建立损伤模型，持续14 d。同时每日腹腔注射1 mL对应剂量的药物。14 d后，所有组常规12 h明暗循环再饲养5 d，采用视网膜电图检查。过量麻醉法处死大鼠制备标本，HE染色，在光学显微镜下观察外核层厚度； CheKine^TM超氧化物歧化酶(SOD)活性检测试剂盒检测SOD活性； Western Blot检测大鼠视网膜Caspase-3、醌氧化还原酶1(NQO1)、谷胱甘肽巯基转移酶(GST)、Bcl-2和Bax蛋白表达量。

结果：蓝光损伤组暗视ERG 3.0、10.0(cd·s)/m²刺激光下b波、明视ERG 3.0(cd·s)/m²刺激光下b波振幅及震荡电位第2个波峰振幅显著低于正常对照组(均P<0.01)，N2L中剂量组较蓝光损伤组振幅显著提高(均P<0.05)，且与正常对照组无显著差异； 蓝光损伤组较正常对照组视网膜ONL厚度下降(P<0.001)，N2L中剂量组厚于蓝光损伤组(P<0.001)，与正常对照组无显著差异； N2L中剂量组超氧化物歧化酶活性显著高于其余5组(P<0.05)； 蓝光损伤组Caspase-3、Bax及NQO1表达量较正常对照组更高(均P<0.01)，N2L中剂量组Bax、Caspase-3表达量较蓝光损伤组显著降低(均P<0.001)，而GST、NQO1及Bcl-2显著增加(均P<0.01)。

结论：2.5 mg/kg N2L能有效拮抗蓝光对SD大鼠视网膜的损伤作用，有望成为其防治药物。

METHODS: A total of 36 specific pathogen free-grade male SD rats of 150-200 g were selected and randomly divided into normal control group, blue light injury group, N2L low-dose group(1.0 mg/kg), N2L medium-dose group(2.5 mg/kg), N2L high-dose group(5.0 mg/kg), and physiological saline group, with 6 rats in each group. The normal control group was reared in a 12 h dark and light cycle, and the rest of the groups received 9 h of daily light exposure, 3 h of blue light irradiation with a wavelength of 455 nm and an intensity of 3000±50 lx, and 12 h of darkness to establish the injury model, and were exposed to light exposure for 14 d. For 14 consecutive durations, a 1 mL dose of the corresponding drug was injected intraperitoneally. The rats were reared for another 5 d with a regular 12 h light-dark cycle and were examined by electroretinography. Specimens were prepared by over anesthesia, HE staining, and the thickness of the outer nuclear layer was observed under a optical microscope; superoxide dismutases(SOD)activity was detected by CheKine^TM SOD Activity Assay Kit; and the retinal Caspase-3, quinone oxidoreductase 1(NQO1), glutathione S transferase(GST), Bcl-2, and Bax protein expression in rat retina were detected by Western blot.

RESULTS: The amplitude of b-wave in dark-vision ERG 3.0 and 10.0(cd·s)/m² stimulated light, b-wave in bright-vision ERG 3.0(cd·s)/m² stimulated light, and the amplitude of the 2nd wave peak of oscillatory potential were significantly lower in blue light injury group than that in the normal control group(all P<0.01), while the amplitude was significantly higher in the N2L medium-dose group than in the blue light injury group(all P<0.05), and was not statistically different from that of the normal control group; the thickness of the retina in the blue light injury group was decreased in the ONL compared with that of the normal control group(P<0.001), while in the N2L medium dose group, it was thicker than that of the blue light injury group(P<0.001), and there was no statistically significant difference from the normal control group; SOD activity was significantly higher in the N2L medium-dose group than in the remaining 5 groups(P<0.05); the expression of Caspase-3, Bax, and NQO1 in the blue light injury group was higher than that of the normal control group(all P<0.01), and expression of Bax and Caspase-3 was significantly lower in the N2L medium-dose group compared with the blue light injury group(all P<0.001), whereas GST, NQO1 and Bcl-2 were significantly increased(all P<0.01).

CONCLUSION:A concentration of 2.5 mg/kg N2L can effectively antagonize the damaging effect of blue light on the retina of SD rats, and it is expected to be a preventive and curative drug for it.