[Experimental study of local administration of silver nanoparticles for the treatment of pyogenic spondylitis]

To establish a proper animal model of pyogenic spondylitis, to evaluate the efficacy of silver nanoparticles for treatment of spinal pyogenic infections, and to explore the distribution of the particles in the body of the animals.

Staphylococcus aureus was inoculated into intervertebral discs of rabbits to establish a spinal pyogenic infection model. These rabbits were divided into Group A [0.1 mg/(kg.d)], Group B [1 mg/(kg.d)], and a Control group. Groups A and B were injected with different doses of silver nanoparticles solution daily at locally infected side. Two weeks later, bacterial cultures, radiographic outcomes, histopathology were analyzed. Atomic absorption spectrometry was utilized to measure silver contents in some vital organs of the rabbits to detect the distribution and accumulation of silver particles.

Staphylococcus aureus (100 CFU/mL), induced 100% pyogenic spondylitis. 1 mg/kg dose of silver nanoparticles solution could effectively inhibit the occurrence of spinal pyogenic infection with the effective rate of 75%. While the effect of 0.1 mg/kg dose of silver nanoparticles solution was less obvious, the efficiency was only 25%. Significant numbers of silver nanoparticles were observed to accumulate in the animal. In the 1 mg/kg group silver was deposited mainly in the spinal cord, liver, kidneys, spleen, and testicles, while in the 0.1 mg/kg group it accumulated only in the spinal cord.

Local administration of silver nanoparticles can effectively prevent and treat pyogenic spondylitis; the particles accumulate in the body commensurate with the administered drug concentration.