OBJECTIVE: To study the histocompatibility and degradation in vivo of a new artificial material, calcium polyphosphate fiber (CPPF), and to provide some experimental basis for further study in tendon tissue engineering. METHODS: CPPF and carbon fiber (CF) as control material were implanted in symmetry part in subcutaneous layer, muscle and Achilles tendon of 20 SD rats. The day of operation, the 4th, 8th, 12th, 16th, and 20th weeks after operation, X-ray examination was performed to detect the density change of materials. Local tissue and materials were observed grossly, and pathological examination was made with HE staining 4, 8, 12, 16 weeks after operation. RESULTS: CPPF degraded completely within 16 weeks in muscle, and in 20 weeks after implantation in Achilles tendon and subcutaneous layer according to X-ray and pathological examination. No calcium phosphate crystal deposit was observed in local tissue. No obviously degradation of CF was found within 20 weeks. Local infiltration of lymphocytes and macrophagocytes around CPPF were much fewer than that of CF. CPPF combined compactly with surrounding hyperplastic tissue. CONCLUSION: CPPF degrade thoroughly from 16 to 20 weeks without sediment of crystal of calcium phosphate in vivo. CPPF has good histocompatibility and can be used as a scaffold material of tissue engineering.
OBJECTIVE: To study the feasibility of calcium polyphosphate fiber (CPPF) as the scaffold material of tendon tissue engineering. METHODS: CPPF (15 microns in diameter) were woven to form pigtail of 3 mm x 2 mm transverse area; and the tensile strength, porous ratio and permeability ratio were evaluated in vitro. Tendon cells (5 x 10(4)/ml) derived from phalangeal flexor tendon of SD rats were co-culture with CPPF scaffold or CPPF scaffold resurfaced with collagen type-I within 1 week. The co-cultured specimens were examined under optical and electric scanning microscope. RESULTS: The tensile strength of CPPF scaffolds was (122.80 +/- 17.34) N; permeability ratio was 61.56% +/- 14.57%; and porous ratio was 50.29% +/- 8.16%. CPPF had no obvious adhesive interaction with tendon cells, while CPPF of surface modified with collagen type-I showed good adhesive interaction with tendon cells. CONCLUSION: The above results show that CPPF has some good physical characteristics as scaffold of tendon tissue engineering, but its surface should be modified with organic substance or even bioactive factors.