Effects of intraarticular injection of vitallium nanocomposites from metal-on-metal hip prosthesis on the reproductive function of male rats

Abstract

Objective To investigate the effects of intraarticular injection of vitallium (CoCrMo)nanoparticles from metal-on-metal hip prosthesis on the reproductive function of male rats.Methods CoCrMo nanoparticles were made by direct current arc plasma method.Most nanoparticles were round in shape and 50 nm in average size (range,from 20 to 100 nm).Seventy-five male Sprague-Dawley rats (8 weeks old)were randomly divided into 5 even groups.In the control group,physiological saline was injected intraarticularly into the rats once weekly for 10 consecutive weeks; suspension with CoCrMo nanoparticles at different doses (50,250,500 and 1000 μg/kg) was injected respectively in the basic,low,medium and high dose groups in the same manner.At the end of the 1 lth week,the rats were sacrificed for measurement of serumal cobalt and chromium ion concentrations,testosterone level,epididymal sperm motility,and count,abnormality and apoptosis of sperms in all samples.Testicular tissues were harvested for pathological evaluation.Results The serumal cobalt and chromium ion concentrations both increased in parallel with the increased doses of CoCrMo nanoparticles injected (P ＜ 0.05).The serum testosterone level in the high dose group was significantly lower than in the control group; the sperm average path velocity (VAP) and beat cross frequency (BCF) in the medium dose group as well as the VAP,straight line velocity (VSL),curvilinear velocity (VCL) and BCF in the high dose group were significantly iower than in the control group (P ＜ 0.05).The count,abnormality and apoptosis rate of sperms were respectively (62.24 ±21.33) × 106/mL,12.1％ ± 2.7％ and 12.4％ ±4.0％ in the medium dose group,and respectively (59.67±18.86) ×l06/mL,16.0％ ±3.8％ and 12.9％ ±4.4％ in the high dose group,with significant differences from those in the controlgroup [(83.11±23.58) ×106/mL,6.2％ ±2.0％ and6.1％±2.5％] (P ＜0.05).Obvious pathological changes in the testis tissues were observed in the medium and high dose groups but not in the basic and low dose groups.Conclusion Intraarticular injection of CoCrMo nanoparticles at medium and high doses may have negative effects on the reproductive function of male rats. Key words: Vitallium; Nanocomposites; Knee joint; Reproduction; Rats