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BACKGROUND:The anterior cruciate ligament has unique nonlinear mechanical properties under a complex physiological loading environment.Elastin is an important contributor to the mechanical properties of the anterior cruciate ligament,but its mechanical response to the anterior cruciate ligament under axial tension is not clear. OBJECTIVE:To quantitatively analyze the effect of elastin on the tensile mechanical response of the anterior cruciate ligament. METHODS:Elastase solution and control buffer were prepared.The porcine anterior cruciate ligament samples were prepared into small-size samples and randomly soaked in 0,0.1,1.0,2.0,5.0,and 10.0 U/mL elastase solution for 6 hours,and other small samples of the same size were soaked in 2 U/mL elastase solution for 0,1,3,6,9,and 12 hours.To determine suitable soaking conditions for elastin-targeted enzymes and verify the digestive effect,histological staining was used to compare the effects of enzyme treatment on tissue structure and composition.The ligament samples were randomly divided into elastase-treated group and PBS group,and immersed in 2 U/mL elastase solution and PBS buffer for 6 hours,respectively.A mechanical tensile test was performed before and after immersion. RESULTS AND CONCLUSION:(1)The biochemical results showed that being treated in 2 U/mL elastase solution for 6 hours could reduce the elastin content by 31.1%,and had no significant effect on other mechanical-related components in the tissue.(2)The histological results showed that elastase was able to penetrate the tissue,and the loose degree of tissue increased after treatment.(3)In the mechanical results before and after treatment,the mechanical properties of the PBS group decreased significantly,only the low-tension elastic modulus increased significantly and the initial length increased significantly in the elastase-treated group.(4)The intergroup comparison results showed that there was no significant difference between the two groups in pre-treatment,but the low-tension elastic modulus,initial slopes,saturated slopes,and initial length of the elastase-treated group after treatment were significantly higher than those in the PBS group.(5)These results suggest that elastin degradation significantly affects the biomechanical properties of the anterior cruciate ligament and further complements our understanding of the structure-function relationship of the anterior cruciate ligament.
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Objective To confirm the correlation between pre or post processing semen parameters and clinical pregnancy rate in infertile couples with male factors undergoing intrauterine insemination (IUI) .Methods The pregnancy rate based on ovulation in‐ducing agent in infertile couples with male factors infertility per the 2010 world health organization criteria treated with IUI was e‐valuated .One hundred and twenty eight cycles were divided into pregnant group (16 cycles) and non‐pregnant group(112 cycles) . The pre or post processing semen parameters were retrospectively evaluated .Results The overall pregnancy rate was 12 .5% .All parameters in this study has no statistically significant difference between the two groups (P>0 .05) .Logistic multivariate analysis showed that there was no significant correlation between semen parameters and clinical pregnancy rate (P> 0 .05) .Conclusion There are no significant correlations between semen parameters and clinical pregnancy rate when the normal forms of patients with male infertility was 4% or higher .No semen parameters could predict results of clinical pregnancy .