Backgrounds & objectives: Liver damage results in a large accumulation of external cellular matrix that affects the function of this important body organ in a long term and finally stops its function completely. The growth factors existing in platelet extract are more cost-effective, available, and stable than recombinant ones. To determine whether the platelet extract effects on histological changes in liver injury induced by carbon tetrachloride (CCl₄), we used immunohistochemical analysis in male rats.

Methods: In this project the 28 male Wistar rats (250-300 g) were randomly divided into 4 groups, each consisting of 7 animals. The rats were divided into four experimental groups as follows: the first group (sham) intraperitoneally received only olive oil as the solvent of carbon tetrachloride; second group (CCl₄) intraperitoneally received carbon tetrachloride dissolved in olive oil (ratio of about 1: 1) at a concentration of 1 ml/kg and a twice a week for eight weeks; third group subcutaneously received only platelet extract at a concentration of 0.5 ml/kg twice a week for three weeks; and fourth group received both CCl₄ intraperitoneally for eight weeks and platelet extract subcutaneously for last three weeks. After 8 weeks of trial blood and liver sampling were done. Blood samples sent for enzymatic (AST, ALT) tests and liver samples tested for histological and immunohistochemical studies. The data were analyzed using  one-way ANOVA followed by Tukey test by Graph pad Prism 5 software and data were considered significant at p≤ 0.05.

Results: The results show that platelet extract causes a significant (p≤ 0.001) decrease in liver enzymes and albumin improves the function of liver. The level of alfa smooth muscle actin (α-SMA) as an index of hepatic stellate cell activation was decreased by platelet extract administration which eventually reduced the necrosis and fibrosis induced by carbon tetrachloride in studied rats