Establishment And Related Studies Of A Neural Invasion Model For Adenoid Cystic Carcinoma In Nude Mice

Salivary adenoid cystic carcinoma(ACC) has a feature of perineural invasion, This neurotropism has brought great difficulties to the surgeons. the studies on the characteristic of perineural invasion of this kind of tumor have emphasized the tumor cell's peculiar chemotaxis and adhesion to the nerve tissue for a long time. Recently some researchers have found that ACC is characterized by neural invasion with early phase in animal experiments. However, There are still no reports on the effect of neural invasion of adenoid cystic carcinoma in different position of nude mice and the process of neural invasion in ultuamicro morphologically.Objective: To observe and study the formation and neural invasion of ACC in different phase, synthetic analysis the process with neural invasion of adenoid cystic carcinoma.To provide evidence for the understanding of the reasons for perineural invasion in ACC and for the controlling of ACC's invasion to nerves.Methods : 1. Human salivary adenoid cystic carcinoma line Acc-M cells were injected into fifty-six nude mice with intramusculary of one lateral rump and subcutaneous tissue of one lateral face posterior part.The process of tumour growth and relation of neural invasion between the sciatic nerve and the facial nerve were observed by hematoxylin-cosin staining method and pulmonary metastasis weren't detected by naked eye, 7,10,16,20,28,36 days after injection of ACC or at the time of animal death. 2. Thirty nude mice divide equally into three group; Acc-M , Tca-8113 and Eca-109 cells were injected respectively into intramusculary tissue of nearby both sides sciatic nerve of ten nude mice. all nude mice were sacrificed 28 days after inoculation. The circumstance of neural invasion of three different carcinoma were compared.3. Human salivary adenoid cystic carcinoma line Acc-M cells were injected into intramusculary of both sides rump of five nude mice. since tumor can be seen at first, dissection of nude mice to observe their relation between tumor and nerve one time per five days, successive observation have been done for one month, at the same time, function change of all limbs with invaded nerve were observed and compared. 4. Human salivary adenoid cystic carcinoma line Acc-M cells were injected into intramusculary of both sides rump of five nude mice. the tumor with neural invasion and function handicapped were chosed and resected, distinguish between nerve with tumor and normal nerve in the pathological section under microscope, so as to exploration of perineural induction with ACC through vivo experiment of the nude mouse. 5. Human salivary adenoid cystic carcinoma line Acc-M cells were injected into intramusculary of both sides rump of five nude mouses, tumor with neural invasion and function handicapped were chosed and resected, by means of transmission electron microscope to observe process of neural invasion of adonoid cystic carcinoma.Results: 1. The tumor take rate was 71. 4% (20/28), neural invasion rate 53.6% (15/28) and functional handicapped rate 10. 7 % (3/28) in nude mice of sciatic nerve group, whereas the tumor take rate was 82. 1% (23/28), neural invasion rate17. 9% (5/28) and not detected functional handicapped in nude mouse of the facial neural group, but pulmonary metastasis weren't found in all nude mouse. 2. 90% of mice with tumor presented neural invasion in Acc-M group, obviously more than 15 % of that in Tca-8113 group and 10 % of that in Eca-109 group (P<0.001) . 3. ACC cell produce invasion at the center of nerve stem.4. Generally, density of innervation in tumor with nerve higher than in normal nerve. 5. tumour cell invade among neurofibrilla through destroy epineurium and perineurium, dissolution and absorption of neural sheath and axon denaturation at the form of phagotrophy in the end.Conclusion : 1. For the first time, we conclude that this model is a good neural invasion model of human salivary adenoid cystic carcinoma, it should be useful to investigate the mechanisms of neural invasion and develop a new therapeutic approach for human salivary adenoid cystic carcinoma. 2. For the first time, we found that neurotropism of ACC working at the way of wraping nerve while which be grewing, and neural invasion is specific biological behaviour of adonoid cystic carcinoma. 3. For the first time, we found that salivary adonoid cystic carcinoma cell is characterized by neural phagocytosis in the observation of electron micronscope, which play a very important role in the course of neural invasion.