[The expression of substance P in airway mucosa of guinea pigs with repetitive esophageal stimulation by hydrochloric acid].
OBJECTIVE
To observe the expression of substance P (SP) in the airway mucosa of guinea pigs with repetitive esophageal stimulation by hydrochloric acid (HCL).


METHODS
Twenty adult guinea pigs were randomly divided into 2 groups (n = 10 each): (1) The HCL model group: On the day of experimentation, guinea pigs were maintained under ketamine anesthesia. A 5F catheter was inserted orally into the lumen of the middle and lower esophagus. The esophagus of each animal was perfused with HCl-P for 20 min/d for 14 d. (2) The PBS control group: The esophagus of each animal was perfused with PBS instead. The bronchial responsiveness to Ach given intravenously with increasing doses (3.125, 6.25, 12.5, 25, 50, 100 microg/kg) was measured after the last perfusion. The left lung was isolated for pathological examination. Lung sections were stained with hematoxylin and eosin, and other sections were prepared for immunohistochemistry using monoclonal antibodies against SP.


RESULTS
In response to increasing doses of ACh, all guinea pigs showed dose-dependent increases in R(L). However, when the dose of ACh was increased to 25 microg/kg, the airway responsiveness increased significantly in the HCl-P model animals compared with the PBS control group (t values = 43.057, 51.410, 57.359 respectively, all P<0.01). The mean gray values of SP decreased significantly in the tracheal epithelia and the distal airway walls of the model group compared with the PBS control group (t values = 3.44, 2.16 respectively, all P<0.01).


CONCLUSIONS
There was airway neurogenic inflammation in guinea pigs with repetitive esophageal stimulation by HCL, which maybe closely related to the pathogenesis of gastro-esophageal reflux disease.
Li
Qin-zi
QZ
China Medical University Institute of Respiratory Disease, First Affiliated Hospital of China Medical University, Shenyang 110001, China.
Kong
Ling-fei
LF
Zhang
Shu-na
SN
Zhong
Zhao-shuang
ZS
Zhang
Bao-hui
BH
Liu
Xiao-feng
XF
D000818:Animals; D004947:Esophagus; D005764:Gastroesophageal Reflux / Q000378:metabolism*; D006168:Guinea Pigs; D006851:Hydrochloric Acid; D007249:Inflammation; D008297:Male; D020545:Respiratory Mucosa / Q000378:metabolism*; D013373:Substance P / Q000096:biosynthesis*
D013373:Substance P; D006851:Hydrochloric Acid