The Relationship Between Seminal Plasma Interleukin (IL)-17 Levels And Human Semen Quality

INTRODUCTIONCytokine is a kind of active protein or polypeptide involving in the regulation of testicular function,particularly of occurrence,development and maturation of sperm. Interleukin(IL)-17 is also called cytotoxic T lymphocyte associated antigen 8 (CTLA8),It can induce related cells to secrete IL-6,IL-8 and release IL-1β,IL-6, IL-10,IL-12,TNF-α.It was reported that human seminal plasma contains a repertoire of cytokines including IL-1β,IL-6,IL-8,IL-10,IL-12 and TNF-α,which effects on semen quality and sperm function,and that there is a relationship of IL-17 with endometriosis in women.So far,few investigations have been made concerning this cytokine with regard to reproduction.In order to investigate the effects of IL-17 on sperm quality and male infertility,in the present prospective study,the concentrations of IL-17 were determined in the seminal plasma of donors and male infertility patients from Zhejiang Institute of Planned Parenthood Research.MATERIALS AND METHODSSemen samplesThe semen specimens examined were taken from 45 unmarried donors from Zhejiang Human Sperm Bank and 12 male infertility patients from Zhejiang Institute of Planned Parenthood Research from May 2007 to June 2007.The ages of the donors ranged from 20 to 25(average,21.8),and those of the patients were from 26 to 38(average, 30.1).The genitals,the volume of two testicles,the levels of FSH,LH,T assayed in serum and the results of the urine generally checked were normal in all men.Specimens collectionThey were instructed to abstain from sexual intercourse for 3-5 days prior to collection, Detailed instructions were given to them concerning sterile techniques to prevent contamination of the semen from flora normal to the region of the body.These instructions included thoroughly cleaning the head of the penis.Semen collection was performed by masturbation with clean,dry hands using no creams or lubricants.They were also instructed to direct the entire ejaculate into the container,avoiding contact the interior of the sterile wall of the container.Semen analysisStandard semen analysis was performed according to World Health Organization criteria(WHO,1999)including determination of volume,PH,count,progressive motility and viability(eosin testing)after liquefaction(at 37℃).The viability would be analyzed again after 4h,8h and 24h.Sperm morphology analysisSperm morphology was analyzed according to World Health Organization criteria (WHO,1999).Bacterial countThe semen was allowed to liquefy completely and then inoculations were done with 1:10 diluted,1:100 diluted and 1:1000 diluted samples.The diluent used was sterile distilled water and diluted samples were inoculated on 5%blood agar media.All the media were incubated at 37℃for 48 hours and then examined for any evidence of growth.Preparation of seminal plasmaAt 30 min after collection,liquefied semen samples were centrifuged at 600×g for 20 min.After centrifugation,the clear seminal plasma was collected and stored at -20℃until determination of IL-17,IL-6,IL-8 and TNF-αconcentrations.Determination of IL-17,IL-6,IL-8 and TNF-αin seminal plasmaSeminal plasma levels of IL-17,IL-6,IL-8 and TNF-αwere monitored using an enzyme-linked immunosorbent assay(ELISA)kit. Determination of FSH,LH and T in serumThe levels of FSH,LH and T were measured by Automated Chemiluminescence system.Statistical analysisData were processed by Statistics Package of Social Science(SPSS)11.5.All values were presented as mean±SD.Statistical analysis was conducted using Welch's t-test. The correlation was analyzed by simple linear regression.The level of significance was set at P＜0.05.RESULTSIL-17 determination in seminal plasmaThe median concentration of IL-17 in seminal plasma was 4.39 pg/ml(range 0.45-16.67).Relationship of IL-17 with semen qualityIL-17 concentrations were significantly higher in samples with＜50%progressive motility(6.00±3.97 pg/ml)than those in the group of samples with≧ 50%progressive motility(3.37±2.09pg/ml)(P＜0.01),but there was significant correlation(r=0.108, P＞0.05)There was no relationship between standard morphology and IL-17concentration of sperm.Samples with a PH of～7.5 did not differ significantly with regard to IL-17 concentration.Relationship of IL-17 concentrations with the percentile of dead sperm in 4h,8h and 24h.The percentiles of dead sperm in 4h,8h and 24h were significantly lower in the group of IL-17 concentrations≥4pg/ml than those of IL-17 concentrations＜4pg/ml (P＜0.05)Relationship of IL-17 concentrations with outcome of bacterial countThere was no significant difference of outcome of bacterial count in the group of IL-17 concentrations＜4pg/ml and in that of IL-17 concentrations≥4pg/ml(P＞0.05).Correlation of IL-17 and IL-6,IL-8,TNF-αIL-6 concentrations were significantly higher in the group of IL-17 concentrations＜ 4pg/ml than those of IL-17 concentrations≥4pg/ml(P＜0.05),and IL-6 concentrations were significantly correlated with IL-17 concentrations(r=0.801,P＜0.01).IL-8 concentrations were also significantly higher in the group of IL-17 concentrations＜4pg/ml than those of IL-17 concentrations≥4pg/ml(P＜0.05),and IL-8 concentrations were also significantly correlated with IL-17 concentrations(r=0.579,P＜0.01) Although TNF-αconcentrations were not statistical difference in the group of IL-17 concentrations＜4pg/ml and those of IL-17 concentrations≥4pg/ml(P＞0.05),TNF-αconcentrations were correlated with IL-17 concentrations(r=0.361,P＜0.01).Relationship of IL-17 concentrations in seminal plasma with the levels of FSH,LH and T in serum.There was no significant difference of the levels of FSH,LH and T in serum in the group of IL-17 concentrations＜4pg/ml and in that of IL-17 concentrations≥4pg/ml (P＞0.05).CONCLUSIONSIn the current study,we found that IL-17 existed in human seminal plasma,and its concentration was 4.39±3.20 pg/ml.IL-17 has the relations with progressive motility and the survive time of sperm,but no relations with morphology,concentration of sperm,PH and bacterial count.Although IL-17 concentrations were significantly correlated with IL-6,IL-8,and TNF-αconcentrations,but there were not relationship with FSH,LH,T in serum.