OBJECTIVETo observe the morphological changes of photoreceptor cells in rats with retinitis pigmentosa (RP) induced by N-methyl-N-Nitrosourea (MNU) and the effects of acupuncture against it.

METHODSA total of 16 SD rats were treated with one-time intraperitoneal injection of MNU (50 mg/kg) to induce RP, and randomly divided into an acupuncture group and a model group, 8 rats in each one. In addition, 4 rats were selected as a control group. After model establishment, rats in the acupuncture group were treated with acupuncture at "Xinming-1" (Extra) and "Jingming" (BL 1) for 30 min, once a day for 7 days; rats in the model group and control group received no treatment, and the feeding conditions and fixation were identical as the acupuncture group. 2 h after the end of intervention, rats were sacrificed by cervical dislocation to observe the morphological changes of rhodopsin, rod terminals and rod bipolar cells.

RESULTSDue to the loss of retina photoreceptor cells induced by MNU in rats, in the model group the rhodopsin was stained in residual cell bodies, and there were sporadic rod terminals and little rod bipolar cells; outer segments, inter segments, cell bodies and cell terminals were all affected at different levels. The distribution of rhodopsin was also changed in the acupuncture group, showing more bodies of photoreceptor cells, and the residual rod terminals and rod bipolar cells were more than those in the model group; the injury of retina was less than that in the model group.

CONCLUSIONMNU could lead to a comprehensive injury to the morphology of photoreceptor cells, however, acupuncture is capable of inhibiting morphological changes of photoreceptor cells induced by MNU.