Therapeutic Effect And Mechanism Of Fosfomycin Tromethamine On Chronic Bacterial Prostatitis In Rats

BackgroundChronic prostatitis (CP) is one of the most common urological disease with a high incidence rate in adult men. About 50% of men appeared to have symptoms of prostatitis at some point in life. The etiology of CP is complicated with a prolonged healing and high recurrence rate. The main clinical symptoms of CP is pain and discomfort in the pelvic region, voiding dysfunction, sexual dysfunction and systemic symptoms that seriously affecting the quality of life. The etiology and pathogenesis of CP is not fully understood currently. The possible causes and mechanisms mainly including pathogen infection, autoimmune abnormalities, physical factors, chemical factors, oxidative stress, urine reflux, psychological reasons and neuroendocrine factors. CP complex etiology, pathogenesis and diverse, the current use of combined therapy CP. The treatment of CP mainly including antibiotics, a-blockers, anti-inflammatory therapy and plant preparations, et al. To cure CP, antibiotics must be administered for periods of time, Which mainly including quinolone antibiotics, sulfonamides, macrolides.Fosfomycin (FOM) is an antibiotic with a small molecular weight, rapid absorption, high permeability and widely distributed in tissues, such as kidney, bladder and prostate. Fosfomycin tromethamine (FT) can effectively prevent transurethral resection of bacterial infections and reduce the bacterial resistance to quinolones antibiotics. FOM can be used as a prophylaxis to prevent infection before transrectal ultrasound-guided prostate biopsy and can effectively prevent urinary tract infections postoperative. In addition, FOM can also improve the condition of a patient who diagnosed with a prostate abscess that cause by E. coli resistant to quinolone antibiotics. To another case of prostatitis patients, FT can also get a satisfy results when treated with vancomycin-resistant enterococci. Oral FOM can achieve effective inhibitory concentration in the prostate tissue.Cytokines (such as IL-6, IL-8,TNF-α) are small soluble proteins that secreted by immune and inflammatory cells. They can exert their effects or alter the behavior or properties of the cell itself or other cells by autocrine and paracrine mechanisms. They can be secreted by autocrine and paracrine which can mediated interactions between immune cells. It was thought that cytokines might be found in fluid secreted by the prostate in men with prostatitis such as IL-1β,TNF-α, IL-6, IL-8, IL-10 etc. It indicates that cytokines may involved in the development of CP, and play a foundation for immunotherapy of CP. Now that, CP patients exist anti-inflammatory and proinflammatory cytokine levels imbalance; inflammation of the prostate is to mediated by cytokines. FOM not only exert a direct role in the killing of bacteria, but also inhibit inflammation. Therefore, this study used chronic bacterial prostatitis (CBP) model induced by E. coli, and to explore the therapeutic effects and possibly mechanism of FT on Chronic bacterial prostatitis in rats.Objective1. SD rats were catheterised with a lubricated sterile PE10 and 0.2 ml of the E.coli bacterial suspension was injected into the prostatic urethra to establish a rat model of CBP and to study the effects of FT on the pathology of the prostate tissues in rats CBP;2. To investigate the effects of FT on the microbiological data of the prostate tissues in the rat CBP;3. To investigate the effects of FT on the expression of IL-6, IL-8, TNF-a of the prostate tissue in CBP of rat; 4. To illustrate the efficacy and mechanism of FT on CBP in rats and lay a foundation for the clinical treatment of CBP.Method70 male SD rats were randomly divided into 7 groups,10 in each:Group A: control group (sham group); Group B:the model group; Group C:positive control group (levofloxacin group); D group:FT low-dose group (200mg/kg), course of 14 days; E Group:FT low-dose group (200mg/kg), course of 7 days; F Group:FT high-dose group (300mg/kg),14 days of treatment; G Group:FT low-dose group (300mg/kg), course of 7 days. Then the rats anesthetized with ether and 0.2ml of E. coli bacterial suspension was slowly injected through the catheter into the prostatic urethra by aseptic technique. After the confirming of the model and follwing the treatment. All experimental rats were anaesthetised and exposed the peritoneal cavity and observed the appearance and adhesions of prostate. Then the prostate was excised carefully and the prostate capsule was removed. A portion of the ventral prostate were stained with haematoxylin and eosin and follwed the examination of pathology changes. For bacterial culture, the prostate tissue were homogenated and plated on a MacConkey agar plate and counted the colonies. The expression of interleukin-6, interleukin-8 and tumor necrosis factor-a in prostate tissue were detected by ELISA.All experimental data were analyzed by SPSS 13.0 software, and expressed as mean±standard deviation. Firstly, the homogeneity of data were tested when multiple samples were compared, One-Way ANOVA was used when homogeneity of variance between those groups. Otherwise, rank test was used. LSD test was used to compare pairwise samples. P<0.05 was considered statistically significant.Results1. GeneralAfter the treatment, group A of rats general condition were good, eating as well as moving normal, hair also looking good, limbs feeling strong, like to crowd; group B rats exhibit different degrees of apathetic, lazy, messy hair, reduced activity. Treatment group and positive control group were also exhibit apathetic, lazy move, messy hair, reduced activity, also like to crowd. With the extension of the drug use, the situation of rats improving.2. The general situation of the prostate between groupsThe prostates were pink and soft without any nodule, and it’s easy to separate with no adhesion in group A:;The prostates showed dark, red and nodules, even with some fester, and adhering to the surrounding tissue in group B. The general situation of the prostate in other groups were between group A and group B.3. Histological data of the prostateGroup A shows:structural integrity, pink secretions, without any interstitial edema, a little bit of fibrous tissue and inflammatory cell infiltration; Group B: pathological observation shows that glandular cavity narrow, partly atrophy, occlusion, interstitial fibrous tissue hyperplasia, epithelial cells have different degrees of damage, prostate wall hyperplasia or destruction, and a lot of chronic inflammatory cell infiltrates.Group C:prostate glandular structure almost intact, no basement membrane damage, a little bit of interstitial fibrous tissue proliferation and inflammatory cell infiltration. Group D:basement membrane becoming integrity, epithelia without destroy and, a spot of fibrous tissue and inflammatory cell infiltration. Group E:prostate with vary degrees of damage, there is no damage in basement membrane, a moderate amount of fibrosis and inflammatory cell infiltration in interstitial and glandular cavity. Group F:prostate glandular cavity structure is almost integrity, epithelia without destroy and, a spot of fibrous tissue and inflammatory cell infiltration. Group G:rat prostate glandular cavity structure is basically integrity, no basement membrane damage, a spot of fibrous tissue and inflammatory cell infiltration.4. Microbiological data of the prostate tissuesFollowing prostate tissue culture, CFU counts in the modle group(6.44±0.71) significantly increased compared with those of the positive control group(2.77± 0.84)and treatment group (group D:2.97±0.73; group E:3.20±0.62;group F: 2.75±0.85; group G:3.02±1.06) (P<0.01); When compared to group C, CFU counts in all FT groups except group E were not significantly different (P> 0.05).5. The expression level of IL-6, IL-8, TNF-a in prostate tissue in each group that tested by ELISAELISA assay showed:The level of IL-6, IL-8, TNF-a in the prostste tissue were significantly increased in model group when compared with the control group(P<0.05 or 0.01). The level of IL-8, TNF-a in the prostste tissue were significantly decreased in positive and treatment group when compared with the modle group(P<0.05).Only group F showed a significant reduction of IL-6 when compared with the model group(P<0.05).Conclusion1. Rats were catheterised with a lubricated sterile PE10 and 0.2 ml of the E. coli bacterial suspension containing approximate 1×108 cells/ml was injected into the prostatic urethra can establish a rat model of CBP after 4 weeks.2. The effects of FT on microbiological eradication in the prostate bacteria indicated that FT can treat CBP in rats;3. FT inhibited the levels of IL-6, IL-8, TNF-a in the prostate tissue by immunomodulatory effects, eased the inflammation and promoted the repairing of prostate structural, to achieve the treatment effect of CBP and lay a foundation for clinical studies as well as experiments.4. In summary, FT treat the CBP through:①directly eradicating the bacteria in the prostate;② inhibitting the expression levels of IL-6, IL-8, TNF-a in the prostate to inhibit the Inflammation;③ inhibiting the activation of inflammatiory cells by lipopolysaccharide through eradicating the bacteria in the prostate.