Study On Changes Of Indian Hedgehog Expression In Rat Early Osteoarthritis

Objective:1.To explore the changes of Ihh expression in early stage of osteoarthritis in rats;2.To explore the possibility of early prediction of OA by detecting the level of Ihh expression.Methods:80 SD rats were divided into Sham and 7 ACLT groups consisting of 1 day,3 days,7 days,2 weeks,4 weeks,2 months,3 months.The mRNA levels of Hh signal related gene(Ihh,Smo,Gli1),COL ? and MMP-13 in articular chondrocytes were assayed by real-time PCR.The protein expressionl of Ihh in articular cartilage were assayed by immunohistochemistry.Concentration of Ihh in serum were measured by ELISA.The degeneration of articular cartilage and Agg content were observed with Safranin-O staining.Results:The mRNA level of Ihh was increased first and then decreased,and the level in7-day group(6.58 ± 2.94)was significantly higher than the Sham group(1.03 ±0.27)ng/ml,1-day group(1.71 ± 1.01)and the 3-momth group(2.40 ± 1.81)(P<0.05),and the Ihh downstream genes Smo and Gli1 had similar performance.The concentrations of Ihh in the serum were also increased first and then drops,and the concentrations in 7-day group(0.57 ± 0.32)ng/ml was significantly higher than that in Sham group(0.21 ± 0.08)ng/ml and 3-month group(0.17 ± 0.06)ng/ml(P<0.05),and the3-day group(0.53 ± 0.24)ng/ml`s was significantly higher than that in 3-month roup(0.17 ± 0.06)ng/ml(P<0.05).In immunohistochemistry,the level of Ihh protein expression was the highest in 3-day group and 7-day group.The mRNA levels of hypertrophy markers MMP-13 and Col ? were increased over time;Safranin-O staining and X-ray showed that the joint degeneration was not obvious within a month of ACLT and the degeneration was significant in 3-month group.Conclusion:1.The expression of Ihh in rat OA was significantly increased in the early stage.2.Ihh content in blood is expected to be a convenient means for early detection of OA.