Expression And Significance Of Midkine In Salivary Adenoid Cystic Carcinoma And Updating Of Perineural Invasion Nude Murine Model

Salivary adenoid cystic carcinoma(SACC)is one of the most common malignant tumors of salivary glands,accounting for about 18% of all salivary gland malignancies [1-2].The special nerve invasion characteristics of SACC bring great difficulties to clinical early diagnosis and surgical treatment.The study of the mechanism of perineural invasion(PNI)is of great significance.Midkine(MK)is a kind of autocrine heparin-binding growth factor,which is highly expressed in various solid malignancies such as pancreatic cancer,liver cancer,gastric cancer and breast cancer,which is closely related to the occurrence and development of tumor.At present,there is no report of the correlation between MK and PNI in SACC.And as an important tool in study of PNI mechanism,the in vivo nude murine PNI model can be advanced in rates of tumorigenesis,PNI and disability of hind limb.This study consists of four parts: 1 Expression and significance of Midkine in salivary adenoid cystic carcinomaObjective To study the expression of midkine(MK)in salivary adenoid cystic carcinoma(SACC)and it`s relationship with perineural invasion(PNI).Methods Immunohistochemistry staining(SP)for MK was performed on 35 SACC and 20 normal salivary gland tissues(NSG).Then,the correlation between the expression of MK and PNI was analyzed.Results In SACC,MK was high expressed and the positive rate was 82.9%(29/35)while it was low expressed and the positive rate was 10%(2/20)in NSG,which showed significant difference(P<0.01).There was no relationship between the expression of MK and age,sex,pathologic types(P>0.05),respectively.However,there was significant difference between PNI cases and non-PNI cases(P<0.05).Conclusion MK may be associated with occurrence of SACC,and its overexpression may be contribute to the perineural invasion in SACC patients.2 Expression and significance of Midkine and microvessel density in oral and maxillofacial tumorsObjective: To investigate the expression of MK and microvessel density(MVD)in oral and maxillofacial tumors and their relationship with tumor malignancy.Methods: SP immunohistochemical method was used to detect the expression of MK and MVD in 20 cases of salivary adenoid cystic carcinoma,20 cases of squamous cell carcinoma,15 cases of pleomorphic adenoma and 15 cases of normal salivary gland.As well as the correlation between the expression of MK and MVD were detected.Results: MK was higher in oral and maxillofacial malignant tumors(salivary adenoid cystic carcinoma(P <0.001)and squamous cell carcinoma(P <0.001))than in benign tumor tissues(pleomorphic adenomas)organization and normal salivary gland.There was a positive correlation between MK and MVD in oral and maxillofacial tumors(r = 0.717,P <0.01).Conclusion: MK may play important roles in malignant transformation and tumor angiogenesis in oral and maxillofacial tumors.3 The modification of SACC perineural invasion nude murine modelObjective: To improve the success rates of PNI animal models through using SACC tumor cell lines and improving the way of tumor cell engraftment.Methods: SACC-83,human salivary adenoid cystic carcinoma cell line;SACC-LM,human salivary adenoid cystic carcinoma lung high metastatic cell line were injected into 16 nude mice sciatic nerve under direct vision,respectively.The rates of tumorigenesis,PNI,and disability of hind limb of in vivo nude mice were observed and analyzed.Results: SACC-LM cell line(100%,81.25%,56.25%)was superior to SACC-83 cell line(68.75%,37.5%,18.75%)in terms of tumorigenesis rate,PNI rate and dysfunction rate.And the medium time of tumorigenesis and the medium time of dysfunction were 7 and 22 days,respectively.Conclusion: Using SACC-LM cell line(density 6 × 10~ / ml),which is more stable and more aggressive cell line,can improve the success rate of PNI animal model under direct vision effectively,which can provide a reliable and stable animal model for the study of the mechanism of PNI.4 The neuroelectrophysiological study on the PNI model of nude miceObjective: To investigate the changes of sciatic nerve electrophysiology during the PNI of salivary adenoid cystic carcinoma.Methods: Human salivary adenoid cystic carcinoma lung high metastatic cell line SACC-LM was injected into 18 nude mice close to sciatic nerve under direct invision after skin insicion.Sciatic nerve conduction velocity,latency and amplitude were measured at 0 days,7 days,14 days,18 days,21 days and 28 days,respectively.Results: The electrophysiological parameters of sciatic nerve in nude mice were aggravated with time,the conduction velocity decreased from the 14 th day,the amplitude decreased from the 18 th day,the latency increased from the 21 st day(VS control group,P <0.01).Conclusion: The electrophysiological parameters of neurons in the process of PNI of salivary adenoid cystic carcinoma were changed,while the nerve conduction velocity and amplitude decrease,the latency is increased,and the nerve conduction velocity changes as well as earliest and most sensitive.