RESUMO
OBJECTIVE: To establish a rat model of autoimmune prostatitis using purified prostatic proteins (PPP). METHODS: Thirty-six male Wistar rats were randomized into three groups of equal number to receive intramuscular injection of normal saline (normal control group) and PPP at 15 mg/ml (low-concentration group) and 80 mg/ml (high-concentration group). At 4 weeks after modeling, the rats were sacrificed for HE staining of the prostate tissue and examination of the inflammatory factors IL-8 and IL-10 in the serum, immunoglobulins IgA and IgM, and regulatory T cells Th1/Th2. RESULTS: Three rats died in the high-concentration PPP group but none in the low-concentration PPP and normal control groups. Gross observation of the prostate showed increased volume and hard texture of the prostate in the two PPP groups, but no significant change in the normal controls. Pathological examination exhibited morphological damage to the prostatic tissue and inflammatory cellular infiltration in the experimental rats. The serum level of IL-8 was significantly higher in the low- and high-concentration PPP groups ([129.07 +/- 11.48] and [147.58 +/- 17.70] pg/ml) than in the control ([94.12 +/- 7.04] pg/ml) (P < 0.05), while that of IL-10 was remarkably lower in the former two groups ([227.14 +/- 18.19] and [187.14 +/- 16.32] pg/ml) than in the latter ([252.48 +/- 21.72] pg/ml, P < 0.05). The serum level of IgA was markedly elevated in the low- and high-concentration PPP groups as compared with that in the control ([0.25 +/- 0.37] and [0.31 +/- 0.42] vs [0.19 +/- 0.14] mg/ml, P < 0.05), and so was that of IgM ([0.23 +/- 0.41] and [0.34 +/- 0.58 ] vs [0.17 +/- 0.33] mg/ml, P < 0.05). No significant changes were observed in the levels of regulatory T cells Th1/Th2. CONCLUSION: Both low and high concentrations of purified prostatic proteins can be used for the construction of autoimmune prostatitis models in rats, while low concentration is preferable for its advantages of lower mortality of the rats and inducement of more consistent manifestations of autoimmune prostatitis.