The effects of antirat nasal septum cartilage antisera on facial growth in the rat.

Antirat nasal septum cartilage antisera (RNS-IgG) produced in rabbits by injection of crude antigens derived from rat nasal septum cartilage was cytotoxic for rat chondrocytes in vitro. The effect of this antisera on rat facial growth was tested by injecting three groups of growing rats at 4-day intervals from birth to 30 days. The treatment group (n = 19) received injections of RNS-IgG, one control group (n = 11) received injections of the IgG fraction of preimmune rabbit sera (PI-IgG) and a second control group (n = 16) received injections of normal saline. All animals were killed at the conclusion of the experiment, and lateral and dorsoventral cephalometric radiographs were taken. Statistical difference between treatment and control groups were found for 15 cephalometric measurements. Specifically, snout length (as measured from the intersphenoidal synchondrosis to the upper incisors (is-i) was reduced in animals treated with RNS-IgG compared with both PI-IgG and saline injected controls (p < 0.06, p < 0.005, respectively). In addition, premaxillary length, premaxillary displacement, and bimaxillary width were significantly reduced (p < 0.05) in RNS-IgG treated animals compared with saline injected controls. Bimolar width was reduced (p < 0.05) between RNS-IgG and PI-IgG groups. These results demonstrate that injection of antinasal septum antisera reduces midfacial dimensions in experimental rats and that nonimmune rabbit antisera may have an effect on the growth process. In summary, the results of this pilot study suggest the possibility for using more specific antinasal cartilage antibodies to effect dose-dependent, tissue specific, modulation of facial growth.