Objective    To investigate the changes of transmyocardial channels after being filled with different hydrogel scaffolds by transmyocardial jet revascularization (TMJR) in dogs and the histocompatibility of different hydrogel scaffolds in myocardium.     Methods    Twelve healthy mongrel dogs

with body weight 9 to 13 kg

aged 1 to 2

were randomly divided into 3 groups

agarose hydrogel group (AH group)

fibrin glue group (FG group) and chitosan hydrogel group (CH group)

4 animals in each group. Transmyocardial revascularization in different groups was performed with needle-free systems to jet out different hydrogels. Samples of myocadial tissues of 3 groups were obtained at 2

4

and 6 weeks after operation for hematoxylin eosin (HE) staining and Masson staining to observe the degradation and histocompatibility of the 3 hydrogels in the myocardium and whether the channels in 3 groups could keep patency.     Results    Fibrin glue had been degraded mostly in less than 2 weeks with less inflammatory response and collagen fibers. The channels in this group were almost occluded after degradation. Moreover mural thrombus was found on the endocardial surface. There were much undegraded agarose hydrogel at 6 weeks

with the collagen fibers proliferating in surrounding tissue and the channels being occluded completely. The degradation cycle of chitosan hydrogel was observed at 4 to 6 weeks and the channels kept patency and endothelialization after degradation.     Conclusion    Agarose hydrogel and fibrin glue are not suitable for transmyocardial channel scaffolds

while chitosan hydrogel is a good substance for preparing transmyocardial channels scaffolds.