Abstract: In order to study the effect of boron on micro structure of lymph nodes and retina in rats, 60 weaned clean level SD rats (21 d±2 d) were randomly divided into the control group and experimentalⅠ, Ⅱ, Ⅲ, Ⅳ, Ⅴ groups after adaptive feeding for 1 week, which were respectively added 0, 40, 80, 160, 320, 640 mg/L boron by drinking water. The experiment lasted for 60 d. The results showed that compared with the control group, the quantity and volume of lymphoid nodules were increased with intensive lymphocytes in lymph node cortex, and paracortexes and medullary cord became thick in the experimental Ⅰ and Ⅱ groups, the quantity of cells increased in the ganglion cell layer, inner nuclear layer and outer nuclear layer of well-developed retina. The quantity and volume of lymphoid nodules were decreased in the lymph node cortex, and paracortexes were thinner with loose arrangement of lymphocytes in the experimental Ⅲ group, the retina had minor injury, and the inter nuclear layer became thin, the ganglion cells decreased and loosed. The lymphoid nodules in the lymph node cortex significantly decreased, and germinal center was not obvious or even disappeared, in which the lymphocytes significantly decreased, the paracortexes and the medullary cord became thin, the ganglion cell layer was thinner, and the ganglion cells were decreased with vacuolated cytoplasm, the cells were loosely arranged in the inter nuclear layer and the outer nuclear layer. Above results indicated that addition 40 to 80 mg/L boron promoted the development of lymph node and retina in the rats to some extent, and addition 320 to 640 mg/L boron had obviously damaged effect on the structure of lymph node and retina in the rats.

Key words: boron; rats; lymph nodes; retina; microstructure