The determination of rat hepatic macrophage phenotypes after antigenic stimulation with lipopolysaccharide (LPS)

This study was performed to investigate the M1/M2 macrophage phenotypes in the rat liver after antigenic stimulation by LPS. Twenty-four Spraque-Dawley male rats were used in the study. The rats were randomly divided into 4 groups; Group I: Control-24 hour group, Group II: Control-48 hour group, Group III: LPS-24 hour group. Group IV: LPS-48 hour group. Group I: 1 ml saline was administered intraperitoneally (i.p) to rats in this group and animals were decapitated under anesthesia after 24 hours. Group II: The rats in this group were administered 1 ml of saline i.p and the animals were decapitated 48 hours later under anesthesia. Group III: LPS-24 hour rats were administered i.p. 5 mg / kg LPS (in 1 ml saline) and the animals were decapitated under anesthesia after 24 hours. Group IV: 5 mg / kg LPS (in 1 ml saline) was administered i.p to rats in the LPS-48 hours group and the animals were decapitated under anesthesia after 48 hours. Histopathological examinations were performed on the liver tissue samples obtained. Sinusoidal dilatation, hyperemia and inflammatory cell infiltration were observed in LPS-24 group at the light microscopic level. Hyperemia and inflammatory cell infiltration were observed in LPS-48 group. CD68 immunoreactivity was significantly increased in LPS-24 and LPS-48 groups compared to control groups (p <0.001). CD68 immunoreactivity was significantly increased in the LPS-48 group compared to the LPS-24 group (p <0.001). There was no change in CD204 and CD163 immunoreactivity in the LPS-24 group. CD204 and CD163 immunoreactivity were increased in the LPS-48 group, but this increase was not statistically significant. As a result, after hepatic antigenic stimulation with LPS, rat hepatic macrophage phenotype increased in the direction of M1 polarization. Keywords: Antigen, LPS, Liver, Macrophage, Rat