Objective To investigate the effects of human acellularamnion membrane on SD rat tendon adhesion and to obtain the experimental data for clinical application in preventing postoperative tendon adhesion. Methods The tendons of 28 adult SD rats hindlimb were cut and sutured. The tendons of left hindlimb were encapsulated by human accellular amnion membraneas the experimental group and the ones of the other side were not encapsulatedas control group. The rats were killed 1, 2, 4, 6, 8 and 12 weeks after operation. The results were evaluated grossly and histologically. Results There were no differences in healing of injury tendon and inflammatory response between the two groups. The anatomical and histological results showed the experimental group had less adhesion than the control group(Plt;0.05). Conclusion Human acellular amnion membrane can prevent adhesion of tendonwithout affecting tendon healing and is an optimal biological material to prevent tendon adhesion.
OBJECTIVE: To investigate apoptosis of chondrocytes cultured in vitro and related expression of caspase-3. METHODS: Apoptosis of chondrocytes were detected by flow cytometry analysis and TUNEL staining. The expression of caspase-3 was determined by RT-PCR and Western blot, and caspase-3 protein activity was determined by ELISA. RESULTS: Apoptosis was observed in chondrocytes cultured in vitro from passage 1 to passage 4 at various degrees. The percentage of apoptosis of chondrocytes on day 7 was much higher than that on day 3 (15.7% +/- 0.3% vs 8.9% +/- 0.6%, P lt; 0.01). caspase-3 mRNA and protein expressed in chondrocytes during whole culture process. Along with the culture time extension in vitro, caspase-3 expression and protein activity up-regulated, coincident with apoptosis of chondrocyte. caspase-3 was activated and a fragment of 20 kDa was detected after 7 days of culture. CONCLUSION: caspase-3 is involved in apoptosis of chondrocytes cultured in vitro.
OBJECTIVE: To investigate the effects of dexamethasone on the proliferation and differentiation of bone marrow stromal cells(MSC). METHODS: MSC were isolated and cultured in vitro. After treatment with different concentrations of dexamethasone (0, 10-10, 10-9, 10-8, 10-7 and 10-6 mol/L), the proliferation and alkaline phosphatase (ALP) activity of MSC were measured to evaluate the effect of dexamethasone on the biological characteristics of MSC. RESULTS: Dexamethasone inhibited cell proliferation. With the increase of concentration of dexamethasone, the effect was enhanced, which was more significant when the concentration of dexamethasone was over 10-8 mol/L. At the same time, dexamethasone promoted the activity of ALP. This effect was enhanced with the increase of concentration of dexamethasone, but the alteration was small when the concentration of dexamethasone was over 10-8 mol/L. The effects increased with the time. The activity of ALP was enhanced 2 to 4 times with the dexamethasone for 6 days. CONCLUSION: Dexamethasone inhabit the proliferation of MSC, while induce them to differentiate into osteoblasts. The appropriate concentration of dexamethasone was 10-8 mol/L.