[Embolization of aneurysm by chitosan-glycerophosphate-fibroblast tissue hydrogel, a tissue engineering material: experiment with rabbits].

Objective: To evaluate the feasibility of the injectable thermosetting chitosan-glycerophosphate-fibroblast (C-GP-FB) hydrogel as an embolizing material of intracranial aneurysm.

Methods: 2% chitosan solution and 56% glycerophosphate solution were mixed in different volume ratio to detect the pH, colloidization time at 37 degrees C, and mechanic strength. Fibroblasts were isolated from the skin of a rabbit and cultured with C-GP hydrogel of different ratios so as to determine the best ratio. Six rabbits underwent construction of aneurysm in the right brachiocephalic trunk. Three weeks later C-GP-FB hydrogel was infused into the aneurysm via microtube and balloon. X-ray photography was conducted soon to observe the embolizing effect. Three days, 1 week, and 4 weeks later tea rabbits were killed respectively with their aneurysms taken out to undergo HE staining and microscopy.

Result: When the ratio of C/GP was 7:1 at pH 7.28, the colloidization time was (260+/-18) sec, and the mechanic strength reached 14 kPa. The C/GP volume ratio of 7:1 was regarded as the best ratio. When the fibroblasts were cultured with the C-GP hydrogel with the C/GP volume ratio of 7:1 the survival rate of the fibroblasts reached the peak of (89+/-2.74)%. X-ray photography showed that image of aneurysm failed to be spotted immediately after the infusion of the C-GP hydrogel. HE staining and microscopy showed that C-GP-FB gel had fine visualization under X-ray. Histological section (HE stain) showed that 3 days after the infusion the aneurysms was embolized by the C-GP-FB hydrogel and no obvious inflammatory cell was seen in the arterial wall; the first week there were many cells in the gel, the boundary between the C-GP-FB gel and vessel wall was clear, and the endotheliocytes were complete; and in the fourth week, the boundary between the gel and vessel wall was obscure, slight degradation could be observed in the edge of hydrogel, and immunofluorescence showed that there were many labeled cell in the gel.

Conclusion: In the short term view, C-GP-FB hydrogel can be used to embolize aneurysms, at least with an obvious short-term effect.