Increased capsaicin receptor TRPV1 in the peritoneum of women with chronic pelvic pain.
OBJECTIVE
To investigate the expression of capsaicin receptor [transient receptor potential vanilloid type-1 (TRPV1)] in the peritoneum of women with chronic pelvic pain (CPP).


METHODS
A case-control study was conducted on 25 women with CPP and 10 controls. Samples of the rectouterine excavation (2 cm) were obtained by laparoscopy, fixed in 4% formaldehyde, and underwent immunohistochemistry analysis using rabbit anti-TRPV1 (1:400) polyclonal antibodies and anti-protein gene product 9.5 (PGP 9.5) (1:2000) as a neuronal marker. Ten sequential images of high magnification fields (x40) were captured from each slide and the area identified with the antibody was calculated with Kontron V2.0 software.


RESULTS
Immunoreactivity to TRPV1 was sparsely detected in the nervous tissue and epithelium of endometriotic lesions. The percent area of immunoreactivity for TRPV1 [expressed as median (range)] was greater in specimens from women with CPP, 1.02% (0.54 to 2.93), than from women without the disease, 0.14% (0.07 to 1.12) (P<0.0001). This greater expression was not secondary to an increase in neuronal fibers because there was also a significant difference in the percent area TRPV1:PGP 9.5 ratio between women with CPP, 1.18 (0.26 to 4.63), and controls, 0.15 (0.06 to 0.95) (P=0.0003).


CONCLUSIONS
TRPV1 may play an important role in the maintenance and perpetuation of symptoms in women with CPP. In view of the immunoreactivity detected for TRPV1, the endometriotic lesion may have the ability to interfere with nociception or with the inflammatory peritoneal environment in women with CPP. Further studies are needed to elucidate the participation of TRPV1 in CPP and its association with endometriosis.
Poli-Neto
Omero Benedicto
OB
Department of Surgery, University Hospital, University of São Paulo, SP, Brazil. polineto@fmrp.usp.br
Filho
Antonio Adnor
AA
Rosa e Silva
Júlio César
JC
Barbosa
Hermes de Freitas
Hde F
Candido Dos Reis
Francisco José
FJ
Nogueira
Antonio Alberto
AA