The Expression Of TRPV5 And TRPV6 In Bone Tumors And Its Correlation With Their Mechanisms

Ca²⁺ is a kind of intracellular second messenger, widely exists in many kinds of cell including bacterium and special neuron. The maintenance of body Ca²⁺ is of crucial importance for many physiological functions, including cell proliferation,cell differentiation and apoptosis. Ca²⁺ channel divides into voltage gated Ca²⁺ channel,excitomotor- receptor gated Ca²⁺ channel and mechanically-operated Ca²⁺ channel. Recently more studies concern on voltage gated Ca²⁺ channel. Voltage gated Ca²⁺ channel is generally divided into L, N, P and T type. Long type Ca²⁺ channel is also called as slow channel. The characteristic of long type Ca²⁺ channel is: high threshold value,magnum electric current and long opening hours. The characteristic of transient type Ca²⁺ channel is: low threshold value,diminutive electric current,short opening hours, therefore,called as fast channel. These two kind of Ca²⁺ channel widely exists in many kinds of cell including osteoblast.Recently, researches on Ca²⁺ channels are mainly concentrated to members of the super family of transient receptor potential (TRP) cation channels. Mammal TRP channel proteins are including 6 related protein families: TRPC, TRPV, TRPM, TRPP, TRPN, TRPML, each family also has many subgroups.Two members of the transient receptor potential (TRP) super family, TRPV5 and TRPV6 as the representative transcellular Ca²⁺transporter , are discovered in recent ten years. Experimental studies already confirmed TRPV5, TRPV6 existed in many kinds of species such as rabbit,mouse and human. And also could be found in the organ which has transcellular Ca²⁺ transportation function,including kidney,duodenum,jejunum,colon and bone tissue. In other words, they can be found in nearly all tissues and organs that relate to Ca²⁺transport. Recently, researches on TRPV5 and TRPV6 are mainly concentrated to accommodation and expression in kidney and intestine. However, the proteins involved in transcellular Ca²⁺ transport in bone cells are largely elusive, waiting for further discusses.In specimens of osteogenic sarcoma,giant cell tumor of bone,colon carcinoma,renal carcinoma and femoral head necrotic tissues disposition and expression of TRPV5,TRPV6 were detected based on immuno-histochemical method. These studies exhibited important roles and significances for expression of TRPV5 and TRPV6 in different organization. All specimens were paraffin wax specimen which came from the First Hospital of Jilin University, and passed pathology expert's confirmation. Before surgery all patients had not received radiotherapy or chemotherapy.This experiment used immunohistochemical method SP to detect expression of TRPV5 and TRPV6 in human femoral head necrotic tissues, osteogenic sarcoma,giant cell tumor of bone,colon carcinoma and renalcarcinoma.Result: In giant cell tumor of bone and osteogenic sarcoma tissues TRPV5 and TRPV6 protein were expressed, but there was no expression in two chondroblast osteogenic sarcoma cases. And the masculine spot mainly locates to cell membrane and cytoplasm. In renal carcinoma and colon carcinoma tissues as positive control groups TRPV5 and TRPV6 protein were expressed, and the masculine spot mainly locates to cell membrane and cytoplasm. The expression intensity has the certain difference in each organization and the cell.Expression of TRPV5 and TRPV6 in giant cell tumor of bone and osteogenic sarcoma prompts that TRPV5 and TRPV6 are correlated with occurrence,development or metastasis of these tumors. Further studies are obviously needed to unravel the precise relationship between Ca²⁺ and certain characteristics of tumor. However, Ca²⁺ transport not only relies on TRPV5 and TRPV6 but also neends related proteins, so it needs further studies.