Caracterização de um modelo experimental de neuropatia em ratos diabéticos induzidos pela aloxana

Alloxan as a better option than streptozotocin for studies involving painful diabetic neuropathy

Previous data indicate that the diabetogenic substance streptozotocin might act in nociceptive neurons changing the sensory signal, regardless of hyperglycemia. In the present article the effects of streptozotocin were compared with another diabetogenic drug, alloxan, for diabetes induction in rats. A possible direct effect of these drugs was tested by means of in vivo experiments and in vitro assays using cultured primary nociceptive neurons. Streptozotocin (17.5 and 35 mg/kg), alloxan (15 and 30 mg/kg) or vehicle were injected in adult male rats and the animal groups were separated according to glycemic levels. Body mass, glycemia and paw mechanical sensitivity were evaluated for 5 weeks. Streptozotocin caused an increase in mechanical sensitivity in both hyperglycemic and normoglycemic rats, while alloxan induced mechanical sensitization only in hyperglycemic animals. Injection of both substances induced local inflammation at rat paws; however, only streptozotocin caused significant mechanical sensitization when injected near to sensory neurons at the dorsal root ganglia. Also, streptozotocin treatment induced a reduction in intracellular calcium levels and inhibited capsaicin induced calcium transients and membrane depolarization. Alloxan did not affect calcium levels or membrane potential in primary nociceptive neurons. These findings suggest that alloxan might be a better option for animal studies regarding painful diabetic neuropathy as streptozotocin directly affects nociceptive neurons, probably by modulating TRPV1 channel activation.

Viability of a random pattern dorsal skin flap, in diabetic rats

PURPOSE

Evaluation of the viability of a random pattern dorsal skin flap, in rats with experimentally induced diabetes mellitus.

METHODS

Thirty adult, male, Wistar EPM rats were distributed, at random, in two groups: I--Control (flap elevation) and II--Experimental (flap elevation ten days after alloxan induced diabetes).

RESULTS

The mean areas of necrosis in the different groups were 36.4% (Control) and 52.1% (Experimental).

CONCLUSION

The random pattern dorsal skin flap was less viable in the diabetic rats.

Experimental model of induction of diabetes mellitus in rats

Diabetes mellitus is a potentially morbid condition with high prevalence worldwide, thus being a major medical concern. Experimental models play an important role in understanding such a disease, which is treatable only. This study describes a rat diabetes mellitus model induced by administering a reduced dose of alloxan, thus greatly reducing the animals’ death rate.