Growth rule of activated Schwann cells cultured on Chitosan-collagen film

Jiyin HE; Jie LAO; Yudong GU; Liangfu JIANG; Jifeng LI

ABSTRACT

BACKGROUND:

New-type tissue engineering materials and post-proliferation Schwann cells are implanted into biosynthesis tube for repairing peripheral nerve defect, which are two great developments in the field of artificial biomaterial tube.

OBJECTIVE:

Taking chitosan-collagen as scaffold, activated Schwann cells as seed cells, we are in attempt to observe the affinity between them as well as growth rule of activated Schwann cells on Chitosan-collagen, so as to provide basis for pre-construction of artificial nerve.

DESIGN:

Open experiment.

SETTING:

Department of Hand Surgery, Huashan Hospital Affiliated to Fudan University.MATERIALS This experiment was conducted at the Key Laboratory of Hand Function Reconstruction, Ministry of Public Health from July 2003 to December 2003. Four male SD rats, of clean degree, were used in this experiment. Chitosan-collagen film was made in Qisheng Biomaterial Technique Institute, Shanghai, Schwann cells activator solution was made in our laboratory (self-made).

METHODS:

After rats were anaesthenia, the sciatic nerve was cut off to perform predegeneration for 7 days. Another anaesthenia later, the rats were euthanized. Both sides of sorciatic nerves were cut off quickly and put in the D-HANK's solution containing penicillin and streptomycin.Epineurium was eliminated and chipped into 1 mm pieces, then put in the centrifuge tube containing 5 g/L trypsinase and 0.6 g/L collagenase. 0.5 mL activator solution every 2 mL liquid was added and the activated Schwann cells were harvested with the way of two-step enzymolysis. 2×107 L-1 activated Schwann cells in 200 μL were inoculated to Chitosan-collagen film and Petri dish . Two weeks later, cellular growth was observed under phase contrast microscope and scanning electron microscope. Cellular purity was identified with S-100 staining.MAIN OUTCOME

MEASURES:

① Drawing cell growth curve and confirming in vitro doubling time. ②Observation of activated Schwanri cells under an inverted phase contrast microscope. ③ Observation of activated Schwann cells inoculated on Chitosan-collagen film under scanning electron microscope.

RESULTS:

① Confirmation of in vitro doubling time Concentration of activated Schwann cells inoculated on both Chitosan-collagen and Petri dish was 2×107 L-1, the final concentration was up to 3.0×108 L-1 and 2.0×108 L-1 respectively 2 weeks later. Doubling time of activated Schwann cells cultured on Chitosan-collagen film was 4 days calculated according to DT=(t-t0) lg2/(lgn-lgn0). ②Observation of activated Schwanncells under an inverted microscope 24 hours later, the activated Schwann cells inoculated to Petri dish mostly changed from spherical to long shuttle-shape,mutation appeared and most were two-pole shape, fewer were three-pole shape; Morphologically, there was no significant difference between activated Schwann cells inoculated on Chitosan-collagen film and on Petri dish. Activated Schwann cells inoculated to Chitosan-collagen film were like "words cayed on the sand" under phase contrast microscope and the purity was over 95%. ③ Observation of activated Schwann cells inoculated to Chitosan-collagen under scanning electron microscope Most of activated Schwann cells grew in the introcession of Chitosan-collagen or closely to surface of Chitosan-collagen, presenting regular head-to-end connection and adhesion to Chitosan-collagen film. The cell body was fusiform,with diameter of 4-6 μm, 60-80 μm in length. Cells were shuttle-shape with some small branches. Morphology of Chitosan-collagen film was still complete at week 1.

CONCLUSION:

There exists great affinity between Chitosan-collagen film and high-purity activated Schwann cell; so tissue-engineering scaffold made of the two components probably promote peripheral nerve regeneration.