Cyclosporin A(CsA) as immunosuppressive drug is used to prevent immune reactions after organ transplant. And also It is reported that the effect of CsA on osteoblast differentiation has been controversial according to dosage. The purpose of this study was to examine the effect of various CsA concentrations on osteoblast differentiation. According to different concentration o f CsA, growth curve, apoptosis index MTT assay, ALP activation and osteocalcin secretion, in cultured NHost were analyzed. Treating osteoblasts with low concentrations of CsA increased growth rate, MTT assay activity, ALP activation and osteocalcin protein levels in a dose-dependent manner, while high concentration showed opposite results. Therefore, these results showed that low concentrations of CsA increased osteoblast differentiation, while high concentrations elicited an opposite response, showing inhibition of CsA on osteoblast differentiation. It suggested that different CsA concentrations might play in regulating NHost differentiation, and its specific activation of lower concentration will represent a viable anabolic therapy for bone resorption disease in future.

I. INTRODUCTION
 II. MATERIALS AND METHODS
  1. Cell culture
  2. Cyclospoin A(CsA) Concentration
  3. MTT(5-diphenyl dimethyl-tetrazoliumbromide) Assay
  4. Growth Curve of NHost
  5. Apoptosis Index
  6. Alkalin Phosphatase(ALP) Activity Assay
  7. Osteocalcin Assay
 III. RESULTS
  1. MTT Assay
  2. Growth curve and Apoptosis
  3. ALP Activity and Osteocalcin Secretion
 IV. DISCUSSION
 V. REFERENCES

• 이종헌(Department of Oral Patholgy, Oral Aging Research Center, Dental College, Dankook University) | Chong Heon Lee correspondence