Recipient treatment with acetylcholinesterase inhibitor donepezil attenuates primary graft failure in rats through inhibiting post-transplantational donor heart ischaemia/reperfusion injury.

Abstract

Ischaemia/reperfusion injury may have deleterious consequences on heart transplantation. The underlying causes such as inflammation may also contribute to the pathogenesis of primary or chronic graft failure. We hypothesize that donepezil (DO), a reversible acetylcholinesterase inhibitor that increases cholinergic receptor activation, may protect the transplanted heart through increasing the level of acetylcholine, which in turn inhibits systemic inflammation in the recipients. First, Lewis-Lewis heart transplantation model was successfully established, and 75 rats were randomly assigned into 3 groups: the DO group (received single dose of intragastric DO treatment), the donepezil + methyllycaconitine group (α7 nicotinic acetylcholine receptor inhibitor) and the control group. Ten rats per group were sacrificed at 24 h after drug administration, whereas the rest of the groups were observed 1 month after surgery. The status of inflammation, survival of the graft and function of the graft were examined. Serum tumour necrosis factor α level was significantly lower in the donepezil group when compared with the control group 24 h after first drug administration; this trend was maintained for 1 month (P < 0.001). Furthermore, DO inhibited CD11b/18-positive cell infiltration (P < 0.001) and myocardiocyte apoptosis (as shown by the percentage of terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick-end labelling-positive nuclei, P = 0.039) in the recipient rats at 24 h after the first drug administration. The percentage of cardiac grafts that survived for 1 month in rats given DO alone was significantly higher (80.0%, 33.3% and 26.7% in the DO, donepezil + methyllycaconitine and control groups, respectively, P = 0.014); the fractional shortening value of the DO group was significantly higher than that in the other 2 groups (29.25 ± 1.84%, 17.92 ± 3.69% and 17.07 ± 2.99% in the DO, donepezil + methyllycaconitine and control group, respectively, P < 0.001). The collagen volume fraction was lower in the DO group than in the other 2 groups (P < 0.001). Our results reveal that treatment of the recipient with DO protects the donor hearts for 1 month after transplantation through suppressing the signalling pathway of inflammation. These results suggest that DO is a novel and clinically feasible strategy to protect the donor heart in transplantation in the long term.