| Laparoscopic surgery has shown the advantages of less trauma,faster recovery and shorter hospital stay and has been widely used in abdominal surgery, but the clinical application of the laparoscopic approach in the treatment of colon cancer remains a matter of controversy.The major disputes focus on wether CO2 pneumoperitoneum can promote tumor growth and metastasis,while different animal models result in different reaserch conclusion. At present,there are scare reaserch reports about the effects of the CO2 pneumoperitoneum on tumor growth and metastasis by use of the orthotopic rectal tumor animal model. Objective:(1)To discover the mouse rectal lymphatic drainage routes and the rules of the mouse rectal tumor metastasis via lymphatic. (2) To study the effect of CO2 pneumoperitoneum on rectal malignancy growth and metastasis. Methods:(1)In the first group,female C57BL/6J mice(n=6) were inoculated in rectum with 1×106 B16 melanoma cells submucosally and observed the tumor growth and lymph nodes metastasis.In the second group,female KM mice (n=30) were injected in submucosal layer of the rectum with the methylene blue(0.05ml) and observed the dyed lymph nodes in different times(10,20,30,40,60min). (2) Methods:An intrarectal B16 malignant melanoma cell inoculation was performed in 30 female C57BL/6J mice. One week later,the mice were randomized into three experimental groups: anesthesia control(A 组,n=10),sole CO2 pneumoperitoneum(B 组, n=10) and repeated CO2 pneumoperitoneum(C 组,n=10).Each pneumoperitoneum was established in group B and C with an intraabdominal pressure of 1.5Kpa for 30 minutes.19 days later,the mice were sacrificed and observed the tumor volume and metastatic lymph nodes. Result:(1)In the first group, all experimental animals developed local tumors. Approximately 3 weeks after tumor inoculation, the mice began to die and tumors average diameter was 2.2(range 2.0-2.6) cm and lymph nodes metastases occurred in 5/6 animals, interarterioiliac nodes 5/6,left iliac nodes 3/6,right iliac nodes 3/6,left para-renal nodes 3/6,right para-renal nodes 3/6,left inguinal nodes 3/6,right inguinal nodes 4/6, respectively.In the second group,27 of 30 mice lymph nodes were dyed, interarterioiliac nodes 25/30,left iliac nodes 21/30,right iliac nodes 14/30,left para-renal nodes 5/30,right para-renal nodes 6/30,respectively;no inguinal nodes were dyed. (2) The mean ( ±SD) tumor volume was respectively 893.2 ±607.08mm3,1953.78±909.47mm3,1395.19±1470.84 mm3 ,the tumor volume was significantly increased in the sole CO2 pneumoperitoneum group compared with anesthesia control group(P=0.033).The average number of metastastic lymph nodes was respectively 2.6±1.84,3.89±1.62,4.75±2.12,the postive lymph nodes rate was respectively 37.14%,55.57%,68.86% and compared with anesthesia control group,the postive lymph nodes rate wassignificantly higher in the sole CO2 pneumoperitoneum(P=0.033) and in the repeated CO2 pneumoperitoneum (P=0.001). Conclusion: (1)In the mouse rectal lymphatic drainage and neoplasm metastasis routes, interarterioiliac nodes may be the first level nodes ; iliac nodes the second; para-renal nodes the third.At the same time,the animal model of rectal lymphatic metastasis provides a useful tool for other oncological researchs and is worthy to be further studied. (2) CO2 pneumoperitoneum can promote the growth and lymph node metastasis of rectal malignancy. |
PDF Full Text Request