Objective       To investigate the efficiency of venous injection of bone marrow mesenchymal stem cells (BMSCs) in treatment of rat prostatitis.       Methods      Rat BMSCs were separated with successive adherence method

and then cultured and amplified. Fifty SD rats were randomized into 5 groups (n=10): chronic bacterial prostatitis (CBP) group

CBP+BMSCs group

CBP+microbubble-enhanced therapeutic ultrasound (MEUS) group

CBP+MEUS+BMSCs group and normal control group. The rats in the other 4 groups except for control were injected with E.coli into both sides of prostate under ultrasound guidance to establish prostatitis model (1-14 d after injection was regarded as acute inflammation period

and 4-12 weeks as chronic inflammation period). The rats from control group were injected with the same volume of PBS. Intravenous injection of BMSCs

MEUS and MEUS+BMSCs was performed into prostatitis rats in 28 d after E.coli injection. BMSCs homing to the prostate were observed by small living animal imaging technology. Pathomorphological changes of rat prostate tissue were observed by light microscopy in 2 weeks after BMSCs injection. The mRNA and protein levels of IL-1β and TNF-α in the prostates were determined by RT-PCR and ELISA

respectively.       Results      Histopathological evaluation showed that typical pathological inflammation were observed in CBP

CBP+BMSCs and CBP+MEUS groups

including the change of gland structure

interstitial edema

inflammatory cells infiltration and fibrous hyperplasia

while pathological changes were relieved obviously in CBP+MEUS+BMSCs group. The mRNA expression levels of IL-1β and TNF-α were obviously higher in CBP group (0.282±0.067 and 0.631±0.116)

CBP+BMSCs group (0.893±0.117 and 0.876±0.137)

and CBP+MEUS group (0.683±0.097 and 0.814±0.127) than those in control group (0.282±0.067 and 0.256±0.059) and CBP+MEUS+BMSCs group (0.322±0.086 and 0.313±0.079

all P0.05). The protein contents of IL-1β and TNF-α were remarkably higher in CBP group (315.14±86.08 and 86.41±24.32 pg/mL)

CBP+BMSCs group (278.87±72.04 and 67.77±16.98 pg/mL)

and CBP+MEUS group (321.24±93.12 and 79.14±19.17 pg/mL) than those in control group (43.36±11.35 and 13.26±3.97 pg/mL) and CBP+MEUS+BMSCs group (65.34±17.23 and 19.94±5.37 pg/mL

all P0.01). While

there was no statistically difference in control group and CBP+MEUS+BMSCs group (P0.05).       Conclusion      MEUS promotes the prostate-targeted transplantation of BMSCs

which can reduce the prostatitis-induced inflammation reaction. This may bring a new strategy for the treatment of prostatitis.