| OBJECTIVE:To observe the effect of prostaglandin E2(PGE2)on the histomorphological changes and the expression of IL-1?,IL-10 and TNAP after the intervention of rabbit Achilles tendon tissue,and to explore the role of PGE2 in the development of rabbit Achilles tendon disease,so as to provide experimental basis for the study of the pathogenesis of tendinopathy.METHODS: Forty-eight New Zealand white rabbits were randomly divided into6 groups,including group K(blank control group),group S(normal saline control group),group A(0.5ug/ml PGE2 group),group B(2.5ug/ml PGE2 group),group C(5ug/ml PGE2 group)and group D(10ug/ml PGE2 group),with 8 rabbits in each group.Groups A,B,C and D were treated with 0.2ml PGE2 at A concentration of0.5ug/ml,2.5ug/ml,5ug/ml and 10ug/ml,respectively.Group S was treated with the same amount of normal saline,once A week for 4 weeks.No drug intervention was given to group K.One week after the intervention,the experimental animals were killed,specimens were prepared,indicators were detected and differences between groups were compared.The observation indexes included :(1)the morphology and structure of Achilles tendon were observed by musculoskeletal ultrasound.(2)Histomorphology of Achilles tendon was observed by HE and Masson staining.(3)m RNA expression of type I and III collagen in Achilles tendon was detected by q RT-PCR.(4)The expression levels of IL-1?,IL-10 and TNAP in Achilles tendon tissues were detected by Western Blot.RESULTS:(1)Musculoskeletal ultrasound results: there was no significant change in the morphology and structure of Achilles tendon in group K,S and A;In group B,C and D,the Achilles tendon showed tissue morphologic disorder,structural change,and blood flow signal of exploration and hyperplasia in and around the Achilles tendon;in group C and D,the Achilles tendon was thickened significantly,blood flow signal increased significantly,tendon fiber fracture was visible,and hyperecho area was visible in the tendon.(2)HE and Masson staining results: no significant pathological changes were observed in group K and group S;In group A,the tendon fibers were slightly curled,loosened and the gap increased.In group B,C and D,there were different degrees of disordered arrangement of tendon fibers,structural destruction and relaxation,and nuclear deformation.In group C and D,a large number of tendon fibers were broken and dissolved,and new blood vessels and a small amount of inflammatory cells were visible in part of the field of vision.(3)m RNA expression of type I collagen: compared with K and S groups,there was no significant difference in m RNA expression of type I collagen in group A(P>0.05).Compared with K and S groups,the m RNA expression of type I collagen in groups B,C and D was significantly decreased,and the decrease in group C was the most significant(P<0.05).MRNA expression level of type III collagen: Compared with K and S groups,m RNA expression level of type III collagen in group A had no significant change(P>0.05).Compared with K and S groups,the m RNA expression of type III collagen in groups B,C and D was significantly increased,and the increase in group D was the most significant(P<0.05).MRNA ratio of type III/I collagen:Compared with K and S groups,m RNA ratio of type III/I collagen in group A was slightly increased(P>0.05);Compared with K and S groups,the m RNA ratio of type III/I collagen in groups B,C and D was significantly increased,and the increase in group D was the most significant(P<0.05).(4)Expression of IL-1?: Compared with K and S groups,the expression of IL-1? in A,B,C and D groups was increased(P<0.05).The expression level of IL-1? increased with the increase of PGE2 concentration,and there was significant difference among different concentrations of PGE2 groups(P<0.05).IL-10 protein expression: Compared with K and S groups,IL-10 expression in A,B,C and D groups was increased(P<0.05).As the concentration of PGE2 increased,the expression level of IL-10 also increased gradually.When the concentration of PGE2 was 2.5ug/m L,the expression level of IL-10 reached the peak;when the concentration of PGE2 continued to increase,the expression level of IL-10 gradually decreased(P<0.05).The expression level of TNAP protein in groups A,B,C and D was higher than that in groups K and S(P<0.05).With the increase of PGE2 concentration,the expression level of TNAP also gradually increased,and the difference between groups A,B and C was statistically significant,while the difference between group C and D was not statistically significant.Ratio of IL-1?/IL-10: The ratio of IL-1?/IL-10 showed A downward trend in the interval of group K--group S--group A--group B,and an upward trend in the interval of group B--group C--group D.Except for no statistically significant difference between group S and group K,the differences among other groups were statistically significant.CONCLUSION:(1)Exogenous PGE2 can promote tendinopathy like pathological changes in Achilles tendon tissue in a concentration-dependent manner,that is,low concentration of PGE2 has no obvious effect on the formation of tendinopathy,while medium and high concentration of PGE2 can promote the formation of tendinopathy,and the concentration limit may be 2.5ug/ml.(2)Exogenous PGE2 can cause local inflammatory response of tendon,and higher concentration of PGE2 causes imbalance of inflammatory response,leading to tendon calcification,and eventually tendonopathy.The concentration of PGE2 leading to the imbalance of local inflammatory response may be 2.5ug/ml. |
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