Effect of Da Jianzhongtang on Visceral Pain in Rats with Irritable Bowel Syndrome / 中国实验方剂学杂志

ABSTRACT

Objective:To investigate the effects of Da Jianzhongtang on substance P （SP）， mast cells （MC）， Toll like receptor 2 （TLR2）， TLR4 on MC model and nuclear transcription factor （NF）-<italic>κ</italic>B p65 in visceral pain rats with irritable bowel syndrome （IBS）， and explore its mechanism of action on IBS visceral pain. Method:Forty-eight 3-day-old SD rats were randomly divided into 6 groups： the control group （control）， irritable bowel syndrome group （IBS）， ketotifen group （Ketotifen，0.18 mg·kg^-1）， Da Jianzhongtang low， medium and high dose groups （DJZT-L， DJZT-M， DJZT-H，2.16，1.08，0.54 g·kg^-1）， with 8 rats in each group. Intragastric administration lasted for 2 weeks. Maternal separation method was used to establish the IBS visceral pain model in rats. The visceral sensitivity of rats was evaluated at 60， 40 and 20 mmHg （1 mmHg≈0.133 kPa） with Abdominal wall withdrawal response （AWR） scale. SP and NF-<italic>κ</italic>B p65 protein expression levels in colon tissue were detected with Western blotting technique. TLR2 and TLR4 proteins on mast cell membrane were detected by immunofluorescence staining. The degranulation rate of mast cells in colon tissue was detected by toluidine blue staining. Result:Compared with normal rats， AWR scores of model rats significantly increased at 60， 40， and 20 mmHg pressure （<italic>P</italic><0.05，<italic>P</italic><0.01）， the degranulation rate of mast cells in colon tissue and SP protein expression in colon tissue significantly increased （<italic>P</italic><0.01）， TLR2， TLR4， and nuclear NF-<italic>κ</italic>B p65 expression on mast cell membrane significantly increased （<italic>P</italic><0.01）. Compared with model rats， the AWR scores of DJZT-H group （pressure of 40， 20 mmHg） and DJZT-M group （pressure of 60， 40， 20 mmHg） significantly decreased. Meanwhile， the degranulation rate of colon mast cells， and the SP， TLR2， TLR4， and NF-<italic>κ</italic>B p65 expression also significantly decreased （<italic>P</italic><0.05，<italic>P</italic><0.01）. Conclusion:Da Jianzhongtang can affect mast cell activity and finally decrease visceral pain of IBS rats by down-regulating SP in colon tissue.