Neuropathic
vulvodynia is a state of vulval discomfort characterized by a burning sensation, diffuse
pain,
pruritus or rawness with an acute or chronic onset.
Diabetes mellitus may cause this type of vulvar
pain in several ways, so this study was conducted to evaluate
streptozotocin-induced diabetes as a
neuropathic pain model for
vulvodynia in female rats. The presence of
streptozotocin (50 mg/kg i.p.)-induced diabetes was initially verified by disclosure of pancreatic tissue degeneration,
blood glucose elevation and
body weight loss 5-29 days after a single treatment. Dynamic (shortened paw withdrawal latency to light brushing) and static (diminished von Frey filament threshold pressure)
mechanical allodynia was then confirmed on the plantar foot surface. Subsequently, both static and dynamic
vulvodynia was detected by application of the paradigm to the vulval region. Systemic
gabapentin (75 mg/kg, i.p.) and topical
gabapentin (10 % gel) were finally tested against
allodynia and
vulvodynia. Topical
gabapentin and the control gel vehicle significantly increased paw withdrawal threshold in the case of the static
allodynia model and also paw withdrawal latency in the model for dynamic
allodynia when compared with the
streptozotocin-pretreated group. Likewise, in the case of static and dynamic
vulvodynia, there was a significant antivulvodynia effect of systemic and topical
gabapentin treatment. These outcomes substantiate the value of this model not only for
allodynia but also for
vulvodynia, and this was corroborated by the findings not only with systemic but also with topical
gabapentin.