Involvement of JAK-STAT signaling/function after cyclophosphamide-induced bladder inflammation in female rats

Cheppudira BP, Girard BM, Malley SE, Dattilio A, Schutz KC, May V, Vizzard MA. Involvement of JAK-STAT signaling/function after cyclophosphamide-induced bladder inflammation in female rats. Am J Physiol Renal Physiol 297: F1038-F1044, 2009. First published July 22, 2009; doi: 10.1152/ajprenal. 00110.2009.-Cytokines are upregulated in a variety of inflammatory conditions and cytokine/ receptor interactions can activate JAK-STAT signaling. Previous studies demonstrated upregulation of numerous cytokines in the urinary bladder following cyclophosphamide (CYP)-induced cystitis. The role of JAK-STAT signaling in urinary bladder inflammation and referred somatic sensitivity has not been addressed. The contribution of JAK-STAT signaling pathways in CYP-induced bladder hyperreflexia and referred somatic hypersensitivity was determined in CYPtreated rats using a JAK2 inhibitor, AG490. Acute (4 h; 150 mg/kg ip), intermediate (48 h; 150 mg/kg ip), or chronic (75 mg/kg ip, once every 3 days for 10 days) cystitis was induced in adult, female Wistar rats with CYP treatment. Phosphorylation status of STAT-3 was increased in urinary bladder after CYP-induced cystitis (4 h, 48 h, chronic). Blockade of JAK2 with AG490 (5-15 mg/kg ip or intravesical) significantly (P <= 0.05) reduced bladder hyperreflexia and hind paw sensitivity in CYP-treated rats. These studies demonstrate a potential role for JAK-STAT signaling pathways in bladder hyperreflexia and referred pain induced by CYP-induced bladder inflammation.