| Objective: Gastric cancer that is the most common malignant tumor in alimentary system has higher morbidity and mortality rates than any others. As the clinical evidence showed, the prognosis of the early gastric cancer is better than the late ones after the surgical treatment. the peritoneal metastasis may be the most important key on the prognosis. The omental milky spot take an important role in the process of the peritoneal metastasis .The milky spot is consist of macrophage cell, lymphocyte and the mesenchymal cells which exists in the micrangium. It can participate the autoimmune diseases in the . Under the stimulation of the tumor cell the macrophage cell can excrete many kinds of chemokine ,which can bind with the special receptor on the tumor. So the tumor will firstly located at the milky spot region and form the early metastasis . so we infer that the milky spots may play an important role in the process of tumor peritoneal dissemination.Chemokine is many kinds of micromolecule biologically active peptide,with the similar structure and function,which have many kinds of biologically function. according to the different number and relative location of the cysteine in polypeptide, the chemokine can be divided into four subtype:CX3C/CXC/C/CC. In recent years, more and more evidence shows that the chemokines play an important role of the tumor recurrence and metastasis.CCL22 belongs to the CC subclass, which exist on the surface of the macrophage cell ,T lymphocyte and NK cell. Under the stimulation of the tumor cell,the milky spot will excrete the CCL22. The receptor of CCL22 is CCR4,this receptor also expressed in gastric tumor . Many evidence showed this specific site is important for the early peritoneal metastasis of advanced gastric cancer . The purpose of our experiment is to observe the milky spot from the mice model with gastric cancer peritoneal metastasis, detect the expression of CCL22,CCR4 in the milky spot,show that chemokine mediate tumor cell selectively violate milky spots in the early of peritoneal metastasis.Measure the density of the CCL22 in the ascites, discussing the relationship between CCL22-CCR4 and peritoneal metastasis in gastric cancer. To identify whether the axis is the new target for the treatment of peritoneal metastasis in gastric cancerMethod:To observe the structure of omental milky spot on mice model by scanning electron microscopy,We established the model by injected the active cabon suspension 0.2ml of each mouse,20mins later execute the mouse, to observe the structure of omental milky spot by HE staining.established by intraperitoneal injection of 0.2ml Dil-MFC cells(CCR4 expression positive,5×106 cells) ;In 48 hours after Mouse were sacrificed.To compare the expression of CCR4 and CCL22 between the milky spots region and other part of the greater omentum by Immunohistochemistry method.Then the animal groups are divided into two parts ,the experimental group was established by intraperitoneal injection of 0.2ml MFC cells(5×106 cells),the saline control groupwas reived saline by intraperitoneal injection.The concentration of CCL22 in ascitic fluid was measured in the 615 mice injected MFC 6,8,10 days after and the saline group.Result:1. Through electron microscope observation, it reveals that milky spots were cobblestone appearance, showing a large number of macrophages, the surface displaying many filamentous cytoplasmic processes, clear space adjacent cells,cracks and pore-phase interval. Around a small round or oval with lymphocytes and endothelial cellsare not continuous;.2. HE staining in the omental milky spots to bring the edge of the fat, oval shaped, which is swallowed or wrapped black carbon particles, surrounded by omental fat cells on the formation of fat vacuoles.3. Immunohistochemical detection found that in the early stages of peritoneal metastasis, the CCL22 and CCR4 expression was positive on milky spots.But Non-milk spot area is not CCL22, and also no gastric cancer cell . 4. Bloody ascites in the experimental group of mice CCL22 concentration in the three time points 6,8,10 days were significantly higher, and significantly statistics (p <0.05). ,Conclusion:1. Through electron microscope observation, it reveals that milky spots are mainly composed of with a few lymphocytes and neutrophils.2. CCR4 expression positive in gastric cancer cells can stimulate the macro- phages milky spots were secreted CCL22 ,show that Chemokine mediate tumor cell selectively violate milky spots in the early of peritoneal metastasis.3. The chemokines CCL22 and its receptor CCR4 is positive in the omental milky spot. So we infer that the CCl22 and CCR4 take an important role in the early peritoneal metastasis . CCR4 may be a potential therapeutic target for peritoneal carcinomatosis. |
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