Abstract: Objective To explore the therapeutic effects of homeopathic and countercurrent administration of β-nicotinamide mononucleotide（NMN） and taurine on experimental silicosis rats. Methods Totally 72 SD specific pathogens free rats,half male and female,sorted by gender and body weight,were randomly divided into a negative control group（not contaminated with dust）,a positive control group,a countercurrent administration group,and a homeopathic administration group using computer randomization,with 18 rats in each group.A rat silicosis model was established by injecting 50 mg/rat of free silica dust into the lungs. On the fourth day after administered,rats in the countercurrent administration group were given NMN solution by gavage in the morning and taurine solution by gavage in the afternoon,the administration sequence of rats in the homeopathic administration group was opposite to that in the countercurrent administration group.And the negative control group and positive control group were given equal amounts of ultrapure water by gavage in the morning and evening. All four groups of rats were administered 5 days a week for a total of 6 weeks. Rats were euthanized 6 weeks after administration,and lung hydroxyproline content,whole lung free silica content,cell count and classification in lung lavage fluid,whole lung dry wet weight,organ coefficient,and pathological changes in lung tissue were detected. Results The lung hydroxyproline content,lung organ coefficient,whole lung wet weight,whole lung dry weight,total cell count,neutrophil rate,and whole lung free silica content in the homeopathic administration group and countertrend administration group were 0.311 mg,0.321 mg,0.622%,0.675%,1.963 g,2.101 g,0.383 g,0.411 g,17.208×10⁹ cells/L,19.375×10⁹ cells/L,57.333%,54.500%,5.650%,and 6.562%,respectively,which were significantly lower than those in the positive control group,and the differences were statistically significant（all P<0.05）.In the positive control group,round or oval nodules were formed in the lung tissue,which were phagocytic cellular nodules,and the alveolar structures in some areas still existed.The experimental group by homeopathic administration and countercurrent administration were similar to those of the positive group,but the degree was relatively mild. Conclusion NMN and taurine have a certain improvement effect and dust removal effect on experimental silicosis rats by homeopathic and countercurrent administration.

Key words: β-nicotinamide mononucleotide, Taurine, Homeopathic administration, Countercurrent administration, Silicon lung rats, Free silicon dioxide