THE ROLE OF BLADDER AFFERENT PATHWAYS IN BLADDER HYPERACTIVITY INDUCED BY THE INTRAVESICAL ADMINISTRATION OF NERVE GROWTH FACTOR:

Changes in bladder nerve-growth factor and p75 genetic expression in streptozotocin-induced diabetic rats

OBJECTIVE

To assess changes associated with diabetes in urinary bladder nerve-growth factor (NGF) and NGF receptor p75NTR expression using a streptozotocin (STZ)-induced diabetic rat model.

MATERIALS AND METHODS

Male Wistar rats (32) were divided into four equal groups: group I, vehicle-treated normal rats; group II, vehicle-treated 9-week STZ-diabetic rats; group III, insulin-treated 9-week STZ-diabetic rats; group IV, phlorizin-treated 9-week STZ-diabetic rats. Bladder NGF levels were measured by enzyme-linked immunosorbent assay. Expressions of the mRNAs that encoded NGF and NGF receptor p75NTR in the rat bladder were evaluated using reverse transcription-polymerase chain reaction.

RESULTS

The mean (SEM) NGF level in the STZ-diabetic rat bladder was significantly lower than in the control group, at 56.56 (8.28) and 84.33 (11.05) pg/microg protein, respectively (P < 0.01). The mRNA expressions of bladder NGF and p75NTR in the diabetic rats were significantly lower than in the control group (P < 0.05 and <0.001, respectively). Treatment with either insulin or phlorizin restored the normal blood sugar level; moreover, the bladder NGF levels and the expressions of both NGF and p75NTR mRNAs were normal.

CONCLUSION

The decrease in the genetic expression of NGF and p75NTR might be responsible for the pathogenesis of diabetic cystopathy while hyperglycaemia is part of the cause of these changes.