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.
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).
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 lens for 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.
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 electroacupuncture group, and the relative expression level of AchRM1 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).
A electroacupuncture 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 AchRM1 receptor in visual cortex in LIM eyes in guinea pigs.