[Correlation of behavioral performance with expressions of substance P and neurokinin-1 receptor in the L5－S2 spinal cord of chronic prostatitis rats]

OBJECTIVE

To investigate the correlation between the behavioral performance and the expressions of substance P (SP) and neurokinin-1 receptor (NK-1R) in the posterior horn of the L5－S2 spinal cord in rats with chronic prostatitis (CP).

METHODS

A CP model was made in 30 adult male SD rats by intraperitoneal injection of 0.5 ml dyphtheria pertussis tetanus (DPT) vaccine and mixed solution of 1 ml prostatein extract and complete adjuvant in a 1∶1 ratio, and another 10 rats were injected with the same volume of normal saline as controls. At 45 (n = 10), 60 (n = 10) and 90 days (n = 10) after modeling, the behavioral changes of the rats were observed by open-field and sucrose consumption tests, the prostatic indexes and levels of serum TNF-α, IL-1β, IL-2 and IL-10 were obtained, and the expressions of SP and NK1-R in the L5－S2 spinal cord were determined by immunohistochemistry.

RESULTS

Compared with the controls, the CP model rats showed obviously decreased horizontal and vertical movement scores and sucrose consumption, particularly in the 90 d group (P < 0.05), significantly reduced prostatic indexes in the 45 d, 60 d and 90 d groups (all P < 0.05), even lower in the 90 d than in the 45 d and 60 d groups (P < 0.05). Edema and lymphocytes were increased in the prostatic tissue with the prolonged time of modeling. The levels of serum TNF-α, IL-1β, IL-2 and IL-10 were markedly elevated in all the CP rats as compared with those in the controls (P < 0.05), and so were the expressions of SP and NK-1R in the L5－S2 spinal cord (P < 0.05), even more significantly in the 90 d than in the 45 d and 60 d groups (P < 0.05).

CONCLUSIONS

Rats with chronic prostatitis are characterized by behavioral manifestation of depression, increased levels of serum TNF-α, IL-1β, IL-2 and IL-10, and a time-dependent upregulation of the expressions of SP and NK-1R in the posterior horn of the L5-S2 spinal cord, which suggests a correlation between the behavioral performance and the expressions of SP and NK-1R in the L5－S2 spinal cord of the rats.