The Expression And Significance Of TRPV5 And Calbindinin-D In Bones

Calcium is an important material element of the human body.Calcium ions metabolism and transition play an important role in avariety of basic biological the processes. Calcium ion metabolism ismainly through bone, small intestine and kidney. TRPV5 is one of the most representative channels of the newlydiscovered trans-membrane calcium ion channels in the decades. Thischannel is a member of the transient receptor potential (TPR)surperfamilly. The new calcium channel TRPV5 is a member ofhighly selective for calcium ions family. This channel exists in almostall the tissues and organs that have the correlation with calcium ionstransfer. It has a very important role of its unique physiologicalfunctions of calcium ion metabolism and bone metabolism. Currentresearch focuses on TRPV5 expression and regulation in the kidneyand intestine. But its expression and many other aspects in bone haveyet to be further explored. The study used Reverse Transcriptase Polymerase ChainReaction (RT-PCR) to detect the TRPV5 mRNA of3 cases of normalcancellated bones and 3 cases of of patho-bones. Experimental resultsshow that: all normal bone specimens, include femur, ilium, show aclear expansion of 320bp TPRV5 specificity belt and calbindin-D9K,calbindin-D28K pecificity belt. Giant cell tumor of bone show TRPV5320bp and calbindin-D9K,calbindin-D28K specificity of expansion,nonossifying fibroma have not TRPV5 320bp and calbindin-D9K,calbindin-D28K specificity of expansion.RT-PCR genetic test is the most commonly used gene expressiondetection methods that sensitive than Northern blot, the majority isusing this gene expression detection method. In order to ensure thereliability of the experimental results of this study take the followingmeasures: After RNA was extracted from the organizationelectrophoresis certify their quality, if RNA subjected to a vague,without a clear 18S and 28S two belt, the RNA samples do not takeinto use to avoid some of which are likely to amplificationpseudogene, to ensure the quality of cDNA. Primer of expansion thepurpose gene is from many laboratories for use. PCR productidentification: all PCR products test with electrophoresis, comparisonwith Marker (standard DNA) under ultraviolet lamp in order todetermine their positive belt. All weaker positive products of the firstround of PCR a second round PCR are done, and if the second roundis still the same, the samples do not include as positive cases in thestudy.From the physiological characteristics of Calcium ion, thecalcium ion channels can be divided into voltage control calcium ionchannels, doors control calcium ion channels and mechanicalmanipulation of calcium ion channels. Generally, voltage controlcalcium ion channels divided into L, N, P and T types. T-type(Transient type) calcium channels are characterized by: low threshold,a small electric currency, short opening hours and therefore also becalled fast channels. TRPV5 is a transient calcium ion channel. It is aprocess of transcellular Ca2+ transport. These highly selectiveepithelial Ca2+channels are part of a three-step process, facilitatingtranscellular Ca2+ transport. After entry of Ca2+ into the cell throughTRPV5, Ca2+ bound to calbindin-D28K and/or calbindin-D9K diffusesto the basolateral membrane. There, Ca2+is extruded via Na+-Ca2+exchanger 1 (NCX1) and ATP-dependent plasma membraneCa2+-ATPase 1b (PMCA1b). So, TRPV5 has an important role in theprocess of transcellular Ca2+transport.From the test, we can draw a conclusion that all normal bonetissue have TRPV5 and calbindin-Ds'mRNA expression. This resultproved that one or multiple cells of the bone have the existence ofcalcium ions transcellular-related TPRV5 and calbindin-D expression.It is possible that there are existences of TPRV5 dependent calciumions transcellular process in bones. Calcium ions transcellular processwith TRPV5 must have relationship with osteogenesis, boneresorption or both. The giant cell tumor of bone, which has TRPV5gene mRNA expression, is osteoclastogenesis tumor. The tumor cellsare osteoclast-like multinucleated giant cells. The tumor is osteolyticlesion. And we found TRPV5 and calbindin under transcriptional level.So we can draw a conclusion that there are existences of calcium ionstranscellular process dependent on TPRV5 and calbindin in giant celltumor of bone. There are no TRPV5 and calbindin expression innonossifying fibroma. Nonossifying fibroma is formed by fibrousconnective tissue. Tumor has not the phenomenon of osteogenesis,which is characteristic of this disease. Such bone tumor has no clearrelevance to osteogenesis and bone resorption. It is belonging tonone-osteogenic tumor. Since the detection samples of tumors bonetissue are small, the larger differences of their histology nature, so itcould not explain TRPV5 gene mRNA expression and the occurrenceof bone tambours relationship.The study confirmed the existence of TRPV5 mRNA expressionin bone tissue,and it also found in giant cell tumor of bone. The studyonly tested TRPV5 gene mRNA expression in normal andpathological bones. Bone tissue cell components are complexity,including the presence of osteoblast, osteoclast and other cells;furtherstuding which cells of those exist TRPV5 expression has greatsignificance. Taking into account the TRPV5 gene mRNA levels arenot strictly consistent with the level of protein expression, proteinlevels for the next step could be testing and understanding TRPV5protein in the cell distribution. TRPV5 channel's found in the bones isimportant for further understanding the role of calcium ions in themetabolism of bone tissue. Further studying the expression of TRPV5regulated by vitamin D3, calcium ion and oestrogenic and studyingthe mechanism of calcium ions regulation the transportation in bonecells is important. It is significance to reveal the concurrency ofosteoporosis and bone tumors and their treatments.In conclusion, our results showed that: Normal bone tissue existcalcium ion transient receptor TRPV5 mRNA stability expression andthe existence of calbindin-Ds'mRNA expression. Giant cell tumor ofbone exist calcium ion transient receptor TRPV5 mRNA stabilityexpression and the existence of calbindin-Ds'mRNA expression. Inthe nonossifying fibroma, there are not TRPV5 and calbindin-Ds'mRNA expression.