Animals will be injected with streptozotocin (STZ) IP or IV once after fasting for 12-18hrs (animals will have free access to food after STZ administration). The following tables show the dose, route, and duration of the study:
|STZ Dose (mg/kg)||Duration of Study||Dose Route|
|40-65mg/kg5-8||Up to 1 week post STZ dose||IV|
|65-75mg/kg1-4,9,10||Up to 4 weeks post STZ dose||IP|
|STZ Dose||Duration of Study||Dose Route|
|150mg/kg11||Up to 1 week post STZ dose||IV|
|100-200mg/kg11-15||Up to 4 weeks post STZ dose||IP|
Prior to STZ injection animals will have a glucose test via tail snip and a von Frey baseline. Animals will be fasted for no longer than 18hrs (typically 12-18hrs) before STZ injection. One hour after injection animals will have free access to food. Depending on the duration of the study (acute vs chronic), animals will be enrolled in the study by glucose test to determine hyperglycemia 24 hrs or 7 days post STZ administration. Following enrollment, animals will continue to get glucose tests and von Frey tested for development of neuropathy as necessary (typically weekly testing in chronic studies). Administration of analgesics will only occur on behavior testing days as a control.
Route of administration: SC, PO, IP, IV
Body weights will be tracked for the duration of the study and von Frey testing will be performed to monitor pain. Depending on the dosing paradigm used, studies may last up to 4 weeks (neuropathy typically peaks 2-4 weeks after IP STZ injection).
Streptozotocin (STZ) is toxic to pancreatic islet insulin-producing b-cells, thus inducing diabetes. Other models of diabetes include genetic models and the use of a prolonged high-fat diet regimen. The STZ model provides a good, simple screening tool to test compounds and to further understand the complex development of neuropathic pain.
Animals will not be supplemented with insulin, except possibly as a control, since it may hinder the development of STZ-induced neuropathy4,5. Also, rats should be housed no more than 2 per cage and should be changed at least 3 times per week (if in standard housing), as they tend to drink a lot and soil their cage quickly.