Effect of intraperitoneal needling on pancreatic beta-cell cytotoxicity mediated via alloxan in mice with an FVB/N genetic background.

The present study investigated whether pre-stimulation with intraperitoneal (i.p.) needling protects against development of diabetes in alloxan-treated transgenic (Tg) mice overexpressing the human Cu/Zn superoxide dismutase gene or non-Tg littermates of the FVB/N strain. Twenty minutes before the alloxan treatment (60 mg/kg) the mice were injected intraperitoneally with 0.05 ml saline while control mice received only the alloxan treatment. Hyperglycemic responses of the saline-injected mice to alloxan were significantly suppressed in the Tg mice (P<0.05). A similar reduction of response was also observed in non-Tg littermates, but the effect was less than that in the Tg mice. This protective effect on the diabetogenic action of alloxan was also demonstrated by an analysis of the number of days positive for urinary glucose, and by immunohistochemical analysis of pancreatic insulin-positive cells. A similar suppressive effect on the hyperglycemic response of alloxan was observed in the mice stimulated by i.p. needling alone. However, suppression of the hyperglycemic response was not observed in ICR mice receiving an i.p. injection. These results suggest that the diabetogenic action of alloxan can be suppressed by i.p. needling-mediated stimulation in mice that have a genetic background of the FVB/N strain. Since a slight protective effects of alloxan-induced diabetes was also observed in the Tg mice compared to FVB/N mice treated with only alloxan, this phenomenon could be more clearly seen in the Tg mice than in non-Tg littermates with an FVB/N background.

Detection of Corynebacterium kutscheri from the oral cavity of rats.

A simple and useful method for the detection of C. kutscheri from the oral cavity of living rats was devised. In 10 sacrificed rats from two naturally and subclinically infected conventional colonies, 10(4.28) or 10(3.84) CFU/ml C. kutscheri were isolated from upper incisor swab extractions, while 10(1.38) or 10(1.58) and < 10 or 10(1.56) CFU/ml from the upper soft palate and pharynx, respectively. In another survey with 26 living animals, which were reared on the same rack, organisms were detected from the upper incisor and gingival swabs in 15 of 26 rats (57.7%). The results were reproducible at a second survey 10 days later. No organisms were isolated from any sites of the orally negative rats. These results indicated that culture of swab specimens from the upper incisors and gingivae of incisors is useful for the detection of C. kutscheri infection in living rats.