[The effects of complete Freund's adjuvant on prevention of pancrentitis and diabetes mellitus in non-obese diabetic mice].

OBJECTIVE

To investigate the role of complete Freund's adjuvant (CFA) in preventing insulitis and diabetes in non-obese diabetic (NOD) mice.

METHODS

Three-week-old female NOD mice were randomly divided into CFA group and phosphate buffered solution (PBS) group. The medications were injected once into the pad of hind foot with 50 microl CFA or 50 microl PBS respectively. Mice of the two groups were sacrificed at 6, 12 and 30 weeks of age respectively. Staining and counting the apoptotic beta cells in islets and evaluating insulitis severity and diabetes incidence were then carried out. The pancreatic sections were stained with hermatoxylin and eosin to score insulitis, and the apoptotic beta cells in islets were confirmed with the di-labeling technique of the TUNEL in situ end-labeling method combined with standard sensitive avidin-biotin complex (sABC) immunohistochemical method.

RESULTS

The insulitis score of CFA-treated mice at 6 and 12 weeks of age was significantly lower than that of PBS-treated mice at the corresponding time respectively (P(6w) < 0.05, P(12w) < 0.05). The apoptotic beta cells were fewer in CFA-treated mice than that in PBS-treated mice at 6 and 12 weeks respectively (P(6w) < 0.01, P(12w) < 0.01). A positive correlation was found between the apoptotic beta cell rates and the insulitis scores at 6 and 12 weeks of age. The diabetes incidence in CFA-treated mice was lower than that in PBS-treated mice (P = 0.001).

CONCLUSIONS

Early treatment with CFA can diminish insulitis and prevent the development of autoimmune diabetes in NOD female mice; this may result from inhibition of apoptotic beta cells.