Research Of Various Mechanical Stimulus On Human Bone Marrow Stem Cells Differentiating Into Chondrocyte

Objectives: It is one of common troublesome cases with cartilage defect or damage.Chondrocytes are seldom capability of migration,poor capability of proliferation,weak capability of regeneration,therefore it is hard to recover itself after cartilage defect or damage.Moreover, cartilage that is formed through autografting or allograft is easy to decay and below the mark in biological quality, abradability, tenacity.With the development of material and life science, people introduce a new method,that is tissue engineering. Bone mesenchymal stem cells(BMSCs) have the multipotential capability of differentiating into bone, cartilage,tendon,adipose and so on.Furthermore,It is easy to culture,nonimmune to react after autograft,convenient to draw the material of BMSCs. Therefore BMSCs are regarded as ideal seed cells.The Objectives of the experiment make the third generation BMSCs adhere onto PLGA to research the influence of various mechanical stimulus on human bone marrow stem cells differentiating into chondrocyte and explore a new channel of curing cartilage damage after BMSCs separating,cultivating,purifying, generating.Methods:To separate,purify and generate BMSCs is by density gradient centrifugation combining the method of adhering to the plastic surfaces.To identify them is by flow cytometric analysis detecting its antigen-CD44,CD45,BMSCs biological characteristics and the capability of oriented differentiation.To make the third generation BMSCs,at a density of 2X107/ml,adhere onto the PLGA that ventage diameter is 200 micrometer and porosity is 85% forms into the compound of BMSCs-PLGA which is exerted 100g, 200g, 300g,respectively.To explore the suitable stimulus on BMSCs differentiating into chondrocyte is through detecting special markers that chondrocyte excretes by the method that HE staining,collagen typeâ…¡immunohistochemistry and Proteoglycan content are evaluated after four weeks. Results:It is successful method to separate and purify BMSCs by density gradient centrifugation combining the method of adhering to the plastic surfaces. BMSCs which are obtained by the method are able to self-renew and generate.However, BMSCs generate slowly when pass to the eighth generation,furthermore,cells gradually become lenity, applanation,nature of refraction degrades and phenomenon of retrogradation takes place. BMSCs adhere onto PLGA well,excrete cell matrix and stuff the ventage of PLGA.Under the condition of the experiment, chondrocyte special matrix which 100g group,200g group,300g group excretes respectively is more than 0g group, P<0.01,the difference is statistically significant. 200g group is more than 100g group and 300g group, P<0.01,the difference is statistically significant. The difference between 100g group and 300g group is not statistically significant, P>0.05.Conclusions: It is convenient and easy method to separate and purify BMSCs from human bone marrow by density gradient centrifugation combining the method of adhering to the plastic surfaces, BMSCs have the capability of renewing themselves,but renew limitedly.PLGA that ventage diameter is 200 micrometer and porosity is 85% provide perfect adhering place for BMSCs so that BMSCs can remain more cell matrix,then this environment is similar to cell living in order to be good for cell growth and development.Meanwhile,due to some strength,PLGA is convenient to carry out tissue transplantation therefore it provides premise for tissue transplantation.Under the experiment condition, mechanical stimulus is in favour of BMSCs differentiating into chondrocyte, nevertheless 200g group is more suitable for BMSCs differentiating into chondrocyte.