The effect of losartan nanoparticles vs losartan on TIMP1 and α-SMA immunohistochemical and gene expression in carbon tetrachloride-induced liver fibrosis.

Liver fibrosis is characterized by scar formation as a response to injury. Although many drugs have demonstrated antifibrotic efficacy in vitro and in animal models, effectively translating these into effective clinical therapies remains a challenge. Nanotechnology offers potential therapeutic approaches for treating liver fibrosis. This study aimed to assess and compare the antifibrotic effects of losartan and losartan nanoparticles (LP-NPs) on CCl4-induced liver fibrosis in rats.Thirty-two adult male Sprague-Dawley rats were divided into four groups: a control group, a CCl4-induced fibrosis group, a losartan-treated group, and an LP-NPs-treated group. Liver fibrosis was induced by CCl4 injections over six weeks. Losartan or LP-NPs were orally administered for four weeks. At the conclusion of the study, rats were euthanized, and blood samples were collected for liver enzyme assessment. Liver specimens were subjected to histopathological examination (H&E, Sirius red staining), immunohistochemistry (α-SMA and TIMP1), and quantitative real-time PCR (qRT-PCR) for gene expression analysis of α-SMA and TIMP1. Morphometrical studies quantified collagen areas in Sirius red-stained sections and optical density of α-SMA and TIMP1 in immunohistochemically stained sections.The results showed that CCl4 induced significantly elevated liver enzymes, severe distortion of hepatic architecture, marked steatosis and fibrosis. Additionally, there was an increase in collagen content, accompanied by strong positive immunostaining and upregulated gene expression of α-SMA and TIMP1. Both losartan and LP-NPs treatments significantly improved these parameters compared to the CCl4-only group. Notably, LP-NPs demonstrated significantly greater improvements in liver enzyme levels, collagen percentage area, and the gene expression of α-SMA and TIMP1 compared to the standard losartan group. However, no significant difference was observed between the two treatments in α-SMA optical density.In conclusion, this investigation demonstrates that nanoformulation significantly enhanced losartan's antifibrotic efficacy. LP-NPs improved liver function and histological architecture, reduced collagen content after CCl4 administration, and demonstrated greater therapeutic efficacy than conventional losartan.