Abstract
Objective: To seek the immune organ spleen function during the tumor growth and metastasis.
Method: 300 Kunming mice, divided into 5 groups: spleen removal; spleen removal before inoculation, inoculation before spleen removal, spleen removal before inoculation+ splenic cells, administration of Chinese medicine. Each group is further separated into subgroups A and B. Ehrlich ascites tumor cell strain was inoculated into the abdominal cavities and ascite cancer cells are extracted from ascetic-type tumor animal abdominal cavity of mice, then 1×104 ml or 1×107ml cancer cells are inoculated through right armpit subcutaneously and abdominal cavity. The spleenectomy was performed by an incision is made into each layer of abdominal wall tissue through left lower abdomen and excise the spleen. Preparations of Splenic Cell Suspension and Supernatant Liquid of Splenic Tissue were made by executing newborn Kunming mice of 24~48h or adult mice and cuting off peripheral envelope and adipose tissue of spleen and making up the splenic cell suspensions of 5×107/ml. Then 2ml splenic cell suspensions into abdominal cavity of each experimental mouse. The following items are observed: success ratio of cancer cell inoculation, occurrence time of subcutaneous tumor nodi and speed of tumor enlargement, diameter and size of subcutaneous tumor nodi; mouse' weight; observe metastasis condition and moving degree; the quality of life, fur color, vitality, state of nutrition, breath, mental state of tumor-bearing mice and survival time of bearing tumor; abdominal shape and prohection of ascetic-type tumor-bearing mice; immunologic functional condition of red blood cells; necropsy and pathological section: tumor's size and weight, infiltrating and metastatic condition, morphological structure and involvement condition of visceral organs; measure the content of ascites; extract tumor tissue, liver, spleen, thymus gland, lung and other visceral organs to carry out the examination of pathological section.
Results: 1. In the control group with spleen (accounts for 7.6%), after inoculation of cancer cells subcutaneously no tumor nodua grew and the mice survives for a long term (i.e. survival time is above 90d); in the group which first removed spleen and then injected splenic tissue(accounts for 25%) , the tumors fail to be inoculated. 2.The tumor which belongs to group of spleen removal before cancer cells inoculation subcutaneously appears first and grows fast. Before the fourteenth day, its tumor volume reaches biggest 14.4±6.2mm compared to 11.43±5.99mm in control group with spleen, P<0.09. On the twentieth day after inoculation, tumors' sizes of control group, group II A1 , group of inoculation before spleen removal reach unanimity: 18.92±9.98mm, 21.12±8.28mm, 19.7±5.9mm, P>0.01, while tumors in the group of injecting supernatant liquid of splenic tissue have the smallest volume 13.89±7.63mm. After cancer cells inoculation of spleen removal group, since the fourteenth day, tumor nodi often bear liquefaction, necrosis and ablation, which result in the shrinkage of tumor volume. 3. All experimental mice in the group of spleen removal before inoculation through abdominal cavity form ascites. The inoculation failure rates of control group with spleen and injection group of supernatant liquid of splenic tissue are 26% and 54% respectively. Survival time for each group's transabdominal inoculation: the mean survival time of group with spleen removal before inoculation is 35.6±18.93 days. While mean survival times of control group with spleen and injection group of supernatant liquid of splenic tissue are 51.46±29.35 days and 57.6±14.85 days respectively, and P<0.05. Significant differences exist among these three groups.4. Pathological changes: Ehrlich ascites tumor cell strain owns features of stable proliferation, strong invasiveness and so on. Subcutaneous inoculation is easy to induce the form of solid tumor which The metastases of cancer cells Metastatic ratios are 20% and 25%. While for mice with transabdominal inoculation, cancer cells easily metastasize to liver, kidney, pancreas, lymph nodes and visceral organs in advanced stage and metastatic ratio is up to 50%; in these group after 7days inoculation, the thymus presents acute and progressive atrophy, thymus' volume shrinks: the diameter of each normal lobule shortens from 5~8cm to about 1mm; the weight reduces from (70±10) mg to (20±5) mg; spleen becomes congested and tumid, the volume enlarges, weight increases, texture becomes fragile and microscopic examination shows the increase of germinal centers and active cell proliferation while on the fourteenth day after inoculation of cancer cells, the spleen also quickly presents progressive atrophy. Its volume shrinks: the weight reduces from (140±15) mg to (50±10) mg. Germinal centers obviously decrease; cell proliferation is suffocated and is hyperplasia of fibrous tissues with gray color and rigid texture. 6. After the removal of spleen, bonding ratio of C3b receptor garland of tumor-bearing mice is on a progressive declining tendency.
Conclusion:(1) The spleen has certain anti-tumor effects. In tumor's early stage, spleen can suppress the growth of tumor. While in advanced stage of the course of disease, the anti-tumor action of spleen weakens or disappears, even can promote the growth of spleen. Tumor is easy to grow in the mouse without spleen after inoculation of tumor and the removal of spleen promotes the growth of tumor and shortens survival times of tumor-bearing mice, consequently leading to easy diffusion and metastasis of tumor.. injection of supernatant liquid of splenic cells will suppress the growth of tumor and prolong survival times of tumor-bearing mice.
(2) Adoptive immunotherapy of tumors with transplantation of homogeneous variant splenic cells of fetal mice can reinforce anti-tumor immunological action of the organism, and suppress the growth of tumor.
(3) There is a negative correlation between anti-tumor action of the organism and the quantity of inoculated cancer cells. The more the quantity of cancer cells, the more easily the immunological action of the organism is suppressed or damaged. The faster the growth rate of tumor, the worse the prognosis.
Citation Format: Jie Xu, Ze Xu, Sitthipol Tovanich, Bin Wu. The spleen function in cancer growth and metastasis prevention. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr A34.
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