Apoptosis of Neutrophils from Diabetic rats

Several studies have shown impairment of neutrophil function that leads to high incidence of infections in diabetes. Neutrophils obtained from streptozotocin (STZ)‐induced diabetic male Wistar rats (65mg/Kg b.w, 6 weeks) were investigated. Diabetic (D) and control (C) rats received an intraperitoneal injection of glycogen solution (1%). After 4 hours, the following parameters were measured: total cell counts in peritoneal lavage; apoptosis process in neutrophils by flow cytometry; activities of caspases 3, 8 and 9 by fluorimeter and expression of the Bax, Fas, p53 and beta2M were also determined by real‐time PCR. Neutrophils from diabetic rats presented a decrease in cell viability and an increase of DNA fragmentation. Phosphatidylserine externalization was observed at the same proportion in neutrophils of C, D and treated D. The caspase 8 activity was decreased (10%) in neutrophils from D rats and these cells presented an increase of caspase 9 activity (26%), whereas the caspase 3 activity was not changed. Neutrophils from D rats presented markedly increased in Bax (9x), Fas (12x) and p53 (13x) mRNA expression. Neutrophils from D treated with insulin (2 to 4 UI/ day) during 6 weeks presented the same changes of the cells from C rat. Therefore, diabetic state induces marked changes in neutrophil apoptosis and this may be important for the impairment in neutrophil function observed under these conditions. Research support by: FAPESP and CNPq