[Preliminary study on in vitro tendon engineering using tenocytes and polyglycolic acids].
OBJECTIVE
To find out the feasibility of tendon engineering in vitro using expanded tenocytes and polyglycolic acids (PGA).


METHODS
Tenocytes were isolated using tissue explant method and expanded in vitro. Tenocytes (20 x 10(6)) at the second passage were collected and then seeded onto PGA unwoven fibers to form a cell-scaffold construct in a shape of tendon. The constructs were cultured in DMEM with 20% FBS for 1 week. The cell-scaffold constructs were then cultured under constant tension generated by a U-shaped spring (n = 5), which served as experimental group, or cultured without tension (n = 4), which served as control group 1. PGA fibers alone were cultured (n = 3), which served as control group 2. Small fragments at the end of the constructs were harvested at 2, 4 and 6 weeks respectively for histological and immunohistochemistry (IHC) analysis. Six-week samples were also evaluated by transmission electron microscope (TEM) and mechanical test.


RESULTS
No obvious difference was observed among the three groups at 2 weeks grossly and histologically as the constructs remained to be mainly undegraded PGA fibers. By 4 weeks, a neo-tendon was formed in the experimental group and control group 1 grossly, and histology and IHC revealed the formation of collagen fibers. In contrast, PGA fibers alone in control group 2 were mostly degraded. At 6 weeks, tendons of control group 1 were much thicker [(2.55 +/- 0.18) mm in diameter] than those of experimental group [(1.44 +/- 0.13) mm in diameter]. Periodical striae were observed in collagen fibers of experimental group and control group 1 by TEM. However, histology of tendons in experimental group revealed longitudinally aliened collagen fibers, which resembled the structure of normal tendon more closely than that of control group 1 tendons. Furthermore, the maximum tensile stress (N/mm(2)) of experimental group (1.107 +/- 0.327) was greater than that of control group 1 (0.294 +/- 0.138) (P < 0.05).


CONCLUSIONS
It is possible to use an engineering to construct tendon tissue in vitro. Periodical strain generated by bioreactor may be the optimal mechanical stimulation, which is currently under investigation.
Cao
De-jun
DJ
Department of Plastic and Reconstructive Surgery, Ninth People's Hospital, Shanghai Second Medical University, Shanghai 200011, China.
Zhai
Hua-ling
HL
Liu
Wei
W
Cui
Lei
L
Zhong
Bin
B
Cao
Yi-lin
YL
D000818:Animals; D002478:Cells, Cultured; D011100:Polyglycolic Acid; D013710:Tendons / Q000166:cytology* / Q000254:growth & development*; D023822:Tissue Engineering / Q000379:methods*
D011100:Polyglycolic Acid