Objective The polymorphism of microsatellite loci among four inbred strains of rats ( HFJ, MIJ, Lewis, F344) was analyzed using 24 pair primers.MethodsTo extract the genomic DNA of MIJ, HFJ, Lewis and F344 inbred rats by standard extraction procedure with phenol/chloroform. 24 microsatellite loci were selected for PCR amplification. Through native polyacrylamide gel electrophoresis and silver staining, microsatellite polymorphism was analyzed in the four strains of inbred rats. ResultsThe amplified products of 24 microsatellite loci among different individual rats of these 4 strains and the same strain rats displayed single allelic gene band. Among the 24 microsatellite loci, it displayed monomorphism between HFJ and MIJ rats. But HFJ and MIJ rats had significant deviations from Lewis and F344 rats. 14 microsatellite loci turned out to be polymorphic, and 10 microsatellite loci displayed monomorphism. ConclusionsThe results of this study suggest that MIJ and HFJ strains basically meet the requirement of inbred strain. The 14 screened loci can be used for genetic monitoring of these inbred rats.