OBJECTIVETo understand the penetrability of trypan blue to the normal prostate as well as to the inflammatory prostate and the prostate with benign hyperplasia in rats.

METHODSSixty SD male rats were randomized into 4 groups: NP (normal prostate) group (n = 15), BP (bacterial prostatitis) group (n = 15), BPH (benign prostatic hyperplasia) group (n = 15), and BPH-BP (benign prostatic hyperplasia with bacterial prostatitis) group (n = 15). Five rats were taken from each group as non-staining controls (NC, n = 5 x 4) and the other 10 were injected by tail intravenation with 1% trypan blue and then the prostates were isolated from the rats killed by anaesthesia after 2 hours. The color of the prostates and other tissues of the animals were observed and the contents of the trypan blue in the tissues of the prostates were determined separately by colorimetry.

RESULTSApart from the tissues of brains and spinal cord the surface and the inner tissues of the prostates with NP, BP, BPH and BPH-BP from the rats injected with the dye were also dyed blue similar to that of the muscles, livers, intestines and others. The content of the trypan blue in the tissues of the prostates with NP, BP and BPH-BP was obviously higher than those with NP and BPH.

CONCLUSIONThe penetrability of trypan blue with properties of ionization and larger molecular weight is high in either the normal prostate or the prostate with BP, BPH and BPH-BP, and much higher in inflammatory prostate than in the normal prostate and the prostate with BPH.