Study On The Effects Of BMP-2 And IGF-1 On Osteoblasts From Normal And Iodine Deficient Rats

To study the effects of BMP-2 and IGF-1 on osteoblasts from normal and iodine deficient rats, iodine deficient developing rat model was established firstly. The osteoblasts separated from normal and iodine deficient rats calvaria were in primary culture, then 0, 50, 100, 200 ng/ml rhBMP-2 and 0, 1, 10, 100, 1000 ng/ml rhIGF-1 were added and the cells were harvested at 24,48 and 72h after the addition. Relative quantification of 0C mRNA was performed by using real-time reverse transcription polymerase chain reaction assays. The expression of 0C mRNA in osteoblasts from normal and iodine deficient rat changed with the duration or concentration of rhBMP-2 and rhIGF-1 (P<0.05) , especially when 48h in both groups and 24h in normal group after rhBMP-2 added and when 10 ng/ml rhIGF-1 was given. The expression of OC mRNA in iodine deficient group was lower than that in normal group (P<0.05) , and the differences between both groups at 24, 48h after rhBMP-2 added and 24h after rhIGF-1 added were significant, while that of 72h after rhBMP-2 added were not.Furthermore, the proliferation of osteoblasts was observed by adding MTT to the primary osteoblasts at 24, 48h after rhBMP-2 and rhIGF-1 were given. Meanwhile, the osteoblasts were crashed and the ALP activities were measured by the method of continuous measurement. The amounts of osteoblasts from normal and iodine deficient rat were significantly increased with the concentration of rhBMP-2 and rhIGF-1 (P<0.05), which implied the proliferation of osteoblasts could be stimulated by rhBMP-2and rhIGF-1. The differences between the proliferation of osteoblasts from normal and iodine deficient groups caused by rhBMP-2 were not significant, while that caused by rhIGF-1 were statistically significant. The proliferation of osteoblasts from ID group was lower than normal group, especially when 1000 ng/ml rhIGF-1 was added. The ALP activities in both groups were significantly increased with the concentration of rhBMP-2 at 48h after the addition (P<0. 05) , while at 72h were not. At 48, 72h after rhIGF-1 was added, the ALP activities in normal group did not change significantly, while in ID group were significantly increased with the concentration of rhIGF-1. The ALP activities caused by rhBMP-2 in ID group were significantly lower than that in normal group (P <0.05) . The differences of the ALP activities between both groups at 48, 72h after 1, 10 ng/ml rhIGF-1 added were statistically significant (/J<0. 05), while that at 48, 72h after 100, 1000 ng/ml rhIGF-1 added were not.In conclusion, BMP-2 and IGF-1 could up-regulate the ALP activity and the expression of OC mRNA of rat osteoblasts, which is affected by the state of iodine nutrition. The response of osteoblasts from iodine deficient rats to BMP-2 and IGF-1 are weaker than that from normal rats, and it suggests the difference of the effects on bone formation of BMP-2 and IGF-1 under different states of iodine nutrition, which has important theoretical meaning and great clinical value.