注射辣椒素於攝護腺引發攝護腺炎使攝護腺之第二型大麻素受體表現上升
林登龍1,2、程威銘3、施郁如1,2、楊長霖1,2、陳光國1,2
臺北榮民總醫院 泌尿部; 國立陽明大學 醫學院 泌尿學科
UP-REGULATION OF PROSTATIC CANNABINOID RECEPTOR TYPE 2 FOLLOWING CAPSAICIN-INDUCED PROSTATITIS IN CASTRATED AND NON-CASTRATED RATS
Alex Tong-Long Lin1,2, Wei-Ming Cheng3, Yu-Ju Shih1,2, CL Yang1,2, Kuang-Kuo Chen1,2
1Department of Urology, Taipei Veterans General Hospital, Taipei, Taiwan
2Department of Urology, School of Medicine, National Yang-Ming University
3 Zhongxiao Branch, Taipei City Hospital
Purpose: The etiology of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is unknown, and there are still no established treatments that consistently relieve patients’ symptoms. Endocannabinoids serves as important modulators of tissue inflammation and pain perception. Manipulation of cannabinoid system had been shown to reduce inflammation and lessen pain perception in some inflammatory disorders. This study investigated the changes of cannabinoid system following capsaicin-induced prostatitis in castrated and non-castrated rats.
Materials and Methods: In adult male Sprague-Dawley rats androgen deprivation was induced with bilateral orchiectomy (OX). At 4 weeks after bilateral OX or sham operation, prostate inflammation was induced by intraprostatic capsaicin injection. Control group received intraprostatic vehicle injection. The expression of cannabinoid receptor type 1(CB1) and 2(CB2), fatty amide hydrolase(FAAH) and cyclooxygenase 2(COX-2) in each group were examined with RT-PCR for mRNA and immunohistochemistry.
Results: Capsaicin injection induced an inflammatory reaction with infiltration of leukocytes. Expression of COX-2 was enhanced following capsaicin injection. Capsaicin injection increased CB2 expression, while the expression of CB1 was not changed. Expression of FAAH, a endocannabinoid degradation enzyme, was reduced following capsaicin injection. Castration induced an atrophic change of the prostate gland. Expression of CB1,CB2 and FAAH was enhanced following castration. Capsaicin injection also induced an inflammatory reaction in the castrated-prostate, but with a lesser degree of leukocyte accumulation as compared with non-castrated group. In the castrated-prostate capsaicin injection induced a further increase of CB2 expression, while expression of CB1 and FAAH was not changed.
Conclusions: The present study demonstrated a consistent up-regulation of CB2 following capsaicin-induced prostatitis in castrated and non-castrated rats. CB2 can be a promising therapeutic target in treating non-bacterial prostatitis.