Objective To review the research and appl ication of functional tissue engineered tendons (FTETs). Methods Recent l iterature concerning the research of FTETs was reviewed and analyzed. Results Functional tissue engineering (FTE) was a new approach that placed an emphasis on the importance of mechanical stress in determining the success of tissue engineered constructs and the effect of tissue remodel ing in vivo. The concept of FTE was introduecd into the research of tissue engineered tendons; by measuring in vivo loads of normal tendon and using the information as a guidel ine, theappropriate tissue engineered tendon which can withstand in vivo loads was designed. It would be possible to solve the problems that the biomechanical function of the tissue engineered tendons could not meet the requirements of the loading environment in vivo. Conclusion FTETs have a more promising future for the treatment of tendon defects.
Objective To investigate an optimal method for SD rat skeletal muscle decellularization. Methods Sixteen SD rats (male and female) weighing 180-200 g were used. Thirty-six skeletal muscle bundles obtained from 10 rats were randomly divided into 3 groups: normal group (group A, n=4) received non-decellularization; time group (group T, n=16) andconcentration group (group C, n=16) underwent decellularization using hypotonic-detergent method. Concentration of sodium dodecyl sulfate (SDS) was 1.0% for T group, which was subdivided into groups T1, T2, T3 and T4 (n=4 per subgroup) according to different processing durations (24, 48, 72 and 96 hours). Group C was treated for 48 hours and subdivided into groups C1, C2, C3 and C4 (n=4 per subgroup) according to different SDS concentrations (0.5%, 1.0%, 1.5% and 2.0%). The muscle bundles of each group underwent HE staining observation and hydroxyproline content detection in order to get the optimal decellularization condition. Seven of 14 complete skeletal muscle bundles obtained from 6 SD rats were treated with the optimal decellularization condition (experimental group), and the rest 7 muscle bundles served as normal control (control group). The muscle bundles of each group were evaluated with gross observation, Masson staining and biomechanical test. Results HE staining: there was no significant difference between groups T1, T2, C1, C2 and C3 and group A in terms of muscle fiber; portion of muscle fibers in group C4 were removed; muscle fibers in group T3 were fully removed with a complete basement membrane structure; muscle fibers of group T4 were fully removed, and the structure of basement membrane was partly damaged. Hydroxyprol ine content detection: there was no significant difference between group A and groups C1, C2, C3, T1 and T2 (P gt; 0.05); significant difference was evident between group A and groups C4, T3 and T4 (P lt; 0.05); the difference between group C4 and groups T3and T4 was significant (P lt; 0.05); no significant difference was evident between group T3 and group T4 (P gt; 0.05). The optimal decellularization condition was 4 , 1.0% SDS and 72 hours according to the results of HE staining and hydroxyproline content detection. Gross observation: the muscle bundles of the experimental group were pall id, half-transparent and fluffier comparing with the control group. Masson staining observation: the collagen fibers of the experimental group had a good continuity, and were fluffier comparing with control group. Biomechanics test: the maximum breaking load of the experimental group and the control group was (1.38 ± 0.35) N and (1.98 ± 0.77) N, respectively; the maximum extension displacement of the experimental group and the control group was (3.19 ± 3.23) mm and (3.56 ± 2.17) mm, respectively; there were no significant differences between two groups (P gt; 0.05). Conclusion Acellular matrix with intact ECM and complete removal of muscle fibers can be obtained by oscillatory treatment of rat skeletal muscle at 4℃ with 1% SDS for 72 hours.