Acupuncture of intraorbital and extraorbital acupoints reduces apoptosis of retinal ganglion by down-regulating expression of Caspase-3 and ratio of Bax/Bcl-2 in rabbits with nonarteritis anterior ischemic optic neuropathy

Abstract

To observe the effect of acupuncture of intraorbital and extraorbital acupoints on apoptosis and expression of Bax, Bcl-2 and Caspase-3 proteins of retinal ganglion tissue in rabbits with nonarteritis anterior ischemic optic neuropathy (NAION), so as to reveal its mechanism underlying improvement of NAION. Female New Zealand rabbits were randomly divided into four groups: model, intraocular needling (ION), extraocular needling (EON), ION＋EON groups (n＝5 per group), and the 5 healthy eyes of those rabbits in the model group were selected to be used as the control group. The NAION model of the right eye was established by photodynamic stroke method. For ION group, acupoints "Jingming" (BL1), "Chengqi" (ST1) and "Qiuhou" (EX-HN7) were needled, and for EON group, "Cuanzhu" (BL2), "Yuyao" (EX-HN4) and "Qiaoming" (EX) were needled with filiform needles, followed by retaining the needles for 30 min. For ION＋EON group, the 6 acupoints were needled simutaneously. The treatment was conducted once daily for 3 days. The apoptosis of retinal ganglion tissue was detected by using TUNEL fluorescence labeling, and the expression of Bax, Bcl-2 and active Caspase-3 in the retinal ganglion were detected by immunohistochemistry. Following modeling and compared with the control group, the number of the apoptotic cells, and the expression levels of Bax and Caspase-3 proteins, as well as the ratio of Bax/Bcl-2 were significantly increased in the model group (P<0.01), while the expression of Bcl-2 was significantly decreased (P<0.01). After intervention, the number of the apoptotic cells in the ION, EON and ION＋EON groups, and the ratio of Bax/Bcl-2 in EON and ION＋EON groups, and the expression of Caspase-3 proteins in the ION and ION＋EON groups were significantly down-regulated (P<0.01, P<0.05), and the expression levels of Bcl-2 in both EON and ION＋EON groups were significantly up-regulated in comparison with the model group (P<0.01). No significant changes were found in the expression levels of Bax in the 3 needling groups relevant to the model group (P>0.05). Acupuncture of intraorbital and extraorbital acupoints can reduce apoptosis of retinal ganglion in NAION rabbits via inhibiting the activation of Caspase-3 protein and ratio of Bax/Bcl-2, and up-regulating the expression of Bcl-2 protein.