Single injection of insulin delays the recurrence of diabetes in syngeneic islet-transplanted diabetic NOD mice.
BACKGROUND
Insulin has been implicated in the pathogenesis of type 1 diabetes and oral administration of insulin has been shown to delay the onset of diabetes in NOD mice. In this study we determined whether a single footpad injection of insulin will protect syngeneic islet grafts from autoimmune destruction when placed under the kidney capsule of diabetic NOD mice.


METHODS
Five hundred islets were transplanted under the kidney capsule of diabetic female NOD mice in conjunction with a single footpad injection of either pork insulin in saline or mixed with incomplete Freund's adjuvant (IFA). Control groups received either IFA or saline alone.


RESULTS
Seven of 11 animals (63.6%) given insulin in IFA exhibit long-term graft survival (>75 days; mean +/- SEM >85.4+/-16.1) whereas only 3 of 12 animals (25.0%) in the IFA group had graft survival longer than 75 days (mean +/- SEM >41.9+/-12.8 days). In contrast, none of the animals that received insulin in saline (17.3+/-2.5 days) and saline only (16.1+2.0 days) exhibit prolonged graft survival.


CONCLUSIONS
These results suggest that a single footpad injection of insulin can protect the islet graft from immune attack in NOD mice.
Rayat
G R
GR
Surgical-Medical Research Institute, Department of Surgery, University of Alberta, Edmonton, Canada.
Singh
B
B
Korbutt
G S
GS
Rajotte
R V
RV
D000818:Animals; D003920:Diabetes Mellitus / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D006085:Graft Survival / Q000187:drug effects; D007328:Insulin / Q000008:administration & dosage*; D016381:Islets of Langerhans Transplantation / Q000276:immunology / Q000502:physiology; D051379:Mice; D016688:Mice, Inbred NOD; D055502:Secondary Prevention; D013997:Time Factors; D014185:Transplantation, Isogeneic
D007328:Insulin