Objective This study was performed to establish and compare guinea pig models of tuberculosis using intranasal and aerosol infection routes at different doses.The overall goal was to provide a foundation for establishing a standardized guinea pig model of tuberculosis for the study of respiratory tract infection.Methods Twenty-four female guinea pigs were randomly divided into six groups of four guinea pigs each.They were then infected with two doses of Mycobacterium tuberculosis through either the aerosol route(groups A,B,and C)or intranasal route(groups D,E,and F).Aerosol infection groups consist of 3 groups:group A(Aerosol control group,uninfected control group),group B(Aerosol low-dose group,5×102 CFU),and group C(Aerosol high-dose group,5×103 CFU)Intranasal infection groups also consist of 3 groups:group D(Intranasal control group,uninfected control group),group E(Intranasal low-dose group,1×104 CFU),and group F(Intranasal high-dose group,5×104 CFU).The clinical manifestations of the guinea pigs were observed after infection.All guinea pigs were euthanized on day 14.Lung,spleen,and liver tissues were obtained for gross examination and histopathological analysis using hematoxylin-eosin staining to identify characteristic lesions associated with tuberculosis.Acid-fast staining was performed on in situ tissues and organs followed by bacterial culture to analyze the bacterial load.Results The guinea pigs in four infection groups(B,C,E,and F)exhibited macroscopic tuberculosis lesions in the lung,spleen,and liver.Histopathological examination revealed the presence of tuberculous granuloma lesions.Acid-fast staining and bacterial load analysis demonstrated that the bacteria were primarily localized in the lung tissue of aerosol-infected groups B and C,with a few also present in the spleen and liver,and the bacterial load was 104～105 CFU/mL.In intranasal infection groups E and F,bacteria were found in the lung,spleen,and liver with a similar bacterial load of 104～105 CFU/mL.There was no significant difference in lesion severity or bacterial load among groups B,C,E,and F;however,groups B,C,and F showed low standard deviations for both pathology and etiology.Conclusions A guinea pig model of acute tuberculosis was successfully established using two doses administered through distinct routes of infection.Pathological examination and pathogenic analysis demonstrated that an aerosol dose of 5×102 CFU of Mtb effectively established a homogeneous model of acute tuberculosis with good consistency among the animals.Additionally,intranasal infection with 5×104 CFU of Mtb produced a relatively uniform model of tuberculosis.Notably,however,aerosol infection at 5×102 CFU progressed to an acute tuberculosis model more rapidly than intranasal infection at 5×104 CFU.