电针对透镜诱导型近视豚鼠视皮层中M1受体表达的抑制作用

Inhitory effect of electroacupuncture on acetylcholine M1 receptor expression in visual cortex of guinea pigswith lens-induced myopia

背景近视的进展中视皮层M受体是否有变化，针灸治疗后视皮层M受体如何变化至今鲜见报道。目的观察电针对透镜诱导型近视（LIM）豚鼠视皮层中M1受体表达的影响。方法采用随机数字表法将48只3周龄三色短毛豚鼠随机分为正常对照组、近视模型组和近视电针组。正常对照组豚鼠未进行任何干预，近视模型组和近视电针组豚鼠右眼配戴-10D负性透镜共4周，近视电针组豚鼠造模即日开始每日针灸太阳穴和合谷穴30rain，共持续4周。分别于造模前和造模后4周采用检影法和A型超声仪测定各组豚鼠的屈光度和眼轴长度。测量完毕后采用过量麻醉法处死豚鼠并获取两侧视皮层组织，采用荧光定量PCR法检测各组豚鼠视皮层中M1受体mRNA的相对表达量；采用ELISA法检测各组视皮层上清液中M1受体蛋白质量浓度。结果造模后4周正常对照组、近视模型组和近视电针组豚鼠右眼的屈光度分别为（0．83±O．36）、（-3．24±0．28）和（-3．30±0．45）D，近视模型组和近视电针组豚鼠右眼的近视屈光度均明显高于正常对照组，差异均有统计学意义（均P=0．000），近视模型组和近视电针组豚鼠右眼的近视屈光度差异无统计学意义（t=O．200，P=0．659）。正常对照组、近视模型组和近视电针组豚鼠右眼的眼轴长度分别为（8．33±0．08）、（8．67±0．14）和（8．60±0．06）mm，其中近视模型组和近视电针组豚鼠右眼的眼轴明显长于正常对照组，差异均有统计学意义（均P=0．000）。正常对照组、近视模型组和近视电针组豚鼠左侧视皮层M1受体mRNA的相对表达量分别为0．79±0．18、1．36±0．23和1．13±O．13，近视模型组豚鼠左侧视皮层M1受体mRNA的相对表达量均明显高于正常对照组，而近视电针组豚鼠左侧视皮层M1受体mRNA的相对表达量明显高于正常对照组而低于近视模型组，差异均有统计学意义（均P〈0．05）。正常对照组、近视模型组和近视电针组豚鼠左侧视皮层M1受体蛋白质量浓度分别为248．00±33．31、455．17±42．40和396．17±47．57，其中近视模型组M1受体蛋白质量浓度明显高于正常对照组而明显低于近视模型组，差异均有统计学意义（均P〈0．05）。结论电针刺激对近视豚鼠的屈光度和眼轴长度无明显影响，近视豚鼠模型视皮层中M1受体表达增高，电针治疗可能通过降低其表达而对近视眼发挥治疗作用。

Background It has not been reported that if the visual cortex M receptor changed during the development of myopia and how it changed if given acupuncture treatment. Objective The aim of this study was to observe the effect of electroacupuncture stimulation on the expression of acetylcholine receptors M1 （AchRM1） in visual cortex of guinea with lens-induced myopia （ LIM）. Methods Forty-eight three-week-old healthy guinea pigs were randomized into the normal control group,the LIM model group and the LIM electroacupuncture group. The right eyes of the guinea pigs were selected as the experimental eyes. LIM was created by monocularly wearing of -10 D lensfor 4 weeks in the right eyes in the LIM model group and LIM electroacupuncture group,and then the acupuncture at the temple and hegu point was performed for 30 minutes per day for consequent 4 weeks, in the LIM electroacupuncture group. The fellow eyes of the guinea pigs were used as the self-control eyes. The refractive power and axial length were examined with retinoscopy and A-type sonography before and 4 weeks after modeling, respectively. The animals were sacrificed by excessive anesthesia at the fourth week after acupuncture and visual vertex tissue was obtained. The expression of M1 receptor mRNA in visual vertex was detected by fluorescence quantitative PCR, and the content of M1 receptor protein in visual vertex was assyed by ELISA. The study protocal was approved by Animal Ethic Committee of Shandong University of Traditional Chinese Medicine, and the use and care complied with Statement of the Association for Research in Vision and Ophthalmology. Results At the fourth week after modeling, the mean diopters were （-3.24±0. 28 ）D and （-3.30±0.45）D in the LIM model group and the LIM electroacupuncture group,which were significantly higher than （0.83±0. 86）D in the normal control group （both at P=0. 000）,and there was no significant difference in the diopter between the LIM model group and the LIM electroacupuncture group （ t = 0. 200, P = 0. 659 ）. The mean axial lengths were （8.67 ±0. 14）mm and （8.60±0. 06）mm in the LIM model group and the LIM electroacupuncture group,which were considerably increased in comparison with （8.33±0. 08）mm in the normal control group （both at P〈0. 05 ）. The relative expression levels of AchRM1 mRNA in visual cortex were 0. 79±0. 18,1.36±0. 23 and 1. 13±0. 13 in the normal control group,LIM model group and LIM eleetroacupuncture group,and the relative expression level of AchRMI mRNA in the LIM electroacupuncture group was significantly higher than that of the normal control group and lower than that of the LIM model group （ both at P〈0.05 ）. In addition,the contents of AchRM1 receptor protein in the visual cortex were 248. 00±33.31,455. 17±42. 40 and 396. 17±47.57 in the normal control group, LIM model group and the LIM electroacupuncture group,with a similar pattern among the groups （both at P〈0. 05）. Conclusions A electroaeupuncture stimmulation do not affect the myopic diopter and axial length in LIM model. The AchRM1 and AchRM1 receptor in the visual cortex up-regulate in LIM eyes, infering that electroacupuncture stimmulation can improve vision by decreasing the level of AehRM1 receptor in visual cortex in LIM eyes in guinea pigs.