The function and mechanism of NALP3 inflammasome in interstitial cystitis/bladder pain syndrome / 中华泌尿外科杂志

ABSTRACT

Objective To acknowledge the NALP3 inflammasome expression and significance in the interstitial cystitis/bladder pain syndrome (IC/PBS).Methods The urine of 16 IC/BPS patients and 16 normal persons was collected to measure the IL-1β content by ELISA.Bladder tissue of 16 IC/BPS patients and para-carcinoma tissue of 16 bladder cancer patients were collected.And the levels of NALP3,caspase1 and IL-1β were detected by Western Blot.60 female rats were randomly divided into control group(bladder was infused with 0.5 ml saline),hyaluronidase group [bladder was infused with 0.5 ml hyaluronidase (4 mg/ml)],NALP3 antagonist group [bladder was infused with 0.5 ml hyaluronidase (4 mg/ml) and Glyburide(10 mg/kg)] and mucosal protectant group [bladder was infused with 0.5 ml hyaluronidase (4 mg/ml) and sodium hyaluronate(0.8 mg/ml)] to carried out the animal experiment,and 15 rats in each group.The models were created by long-term (1 month) intermittent intravesical hyaluronidase infusion.Voiding patterns were investigated by cystometry.Toluidine blue staining was used to detected mast cell’s changes.The levels of NALP3,caspase-1 and IL-1β were determined by Western Blot,HE staining was to detect tissue inflammation of the bladder,and the severity of pain was examined by Von-frey brush by using the strength of 0.07、0.4、1.0 g.The comparison between the chemotaxis of 200 ng,400 ng IL-1β and 200ng SCF IL-1β to mast cells was checked by Transwell experiment.Results The expressions of IL-1β in IC/PBS patients was increased in IC/PBS group than normal control group [(381 ± 112) μg/L vs.(98 ± 40) μg/L,P ＜0.01].The expressions of NALP3,Caspase-1 and IL-lβ had increased in the IC/PBS group than normal group(0.22 ±0.08 vs.0.11 ±0.02,0.25 ±0.03 vs.0.10 ±0.01,0.19 ±0.04 vs.0.11 ± 0.02,P ＜ 0.05)by Western Blot.In the IC/PBS rats,compared with the control group,the intercontraction intervals [(120.0 ± 15.6) s vs.(447.3 ± 24.6) s] and bladder capacity [(0.34 ± 0.02) ml vs.(1.33 ± 0.04) ml] of the model group were significantly decreased (both P ＜ 0.05).In mucosal protectant group and NALP3 antagonist group,the intercontraction intervals [(323 ± 16.3)s,(280 ± 12.5)s] and bladder capacity [(1.14 ± 0.05) ml,(0.84 ± 0.04) ml] were increased compared with control group (P ＜ 0.05).The amount of mast cell in model group were significantly increased than control group (3.4 ±0.8 vs.0.4 ± 0.2,P ＜ 0.05) while in mucosal protectant group (1.8 ± 0.5) and NALP3 antagonist group (1.5 ± 0.7) were decreased compared with control group (P ＜ 0.05).The protein levels in modle group of NALP3 (5.91 ±0.33 vs.1.00 ±0.12),caspase-1 (6.75 ±0.42 vs.1.00 ±0.22) and IL-1β(7.12 ±0.45 vs.1.00 ± 0.18)were increased than control group.In mucosal protectant group and NALP3 antagonist group,theNALP3 (2.921 ±0.21,2.07±0.18),caspase-1 (3.28 ±0.31,2.25 ±0.19) and IL-1β(3.33± 0.41,1.98 ±0.21) were decreased compared with control group.VonFrey pain score in model group were significantly increased than control group(0.07 g7.5 ± 1.8 vs.2.1 ± 0.5,0.4 g9.2 ± 1.9 vs.5.2 ± 1.1,1.0g15.4±3.8 vs.6.8±1.5,P＜0.05) and VonFrey pain score(0.07 g2.4±0.3,2.8± 0.7;0.4 g5.2 ±0.4,6.5 ±1.3;1.0 g6.4 ±0.8,7.3 ±1.1;P＜0.05) in NALP3 antagonist group were significantly decreased.In vitro,Transwell experimental results showed that 400 ng IL-1β of mast cell chemotaxis is similar with that of the 200 ng SCF (3 800 ±400 vs.4 800 ±500,P ＞0.05).Conclusions The levels of NALP3/Caspase-1/IL-1β in the urine of patients with IC/PBS were significantly higher than those in normal control group.NALP3 is activated in chronic cystitis rat model,and related to pain and frequent urination.This may be related to the down-regulation of expression of NALP3,caspase-1,IL-1β,and other inflammatory mediators,and blocking the chemotactic effects of IL-1 β on mast cells.