certain drugs , when administered at therapeutic dose and some in overdose , may injure the liver . a great majority of hepatic adverse reactions seen in clinical practice are unpredictable ( unrelated to a drug s pharmacological characteristics ) and basically result from an interaction of 3 circumstances : a drug with potential to generate hepatotoxic radicals in a genetically susceptible individual under certain environmental factors [ 36 ] . this type of reaction , which occurs only rarely , goes undetected during the drug development process , and hence typically manifests when tens of thousands of patients are exposed to it post - marketing ; this still represents the leading cause for withdrawal of drugs from market . il-8 can be produced by a various types of involved in inflammation , including monocytes and endothelial cells . furthermore , the effects of il-8 in acute phase reaction , inflammatory response , and angiogenesis stimulation have already been determined . additionally , several observations suggest that il-8 pathways might also be involved in the pathogenesis of chronic liver disease . for instance , il-8 levels are increased intrahepatically and in the serum of patients with alcoholic liver disease , probably contributing to hepatic neutrophil accumulation and also exerting systemic actions . in patients with chronic hepatitis c , il-8 serum levels are associated with disease progression and relate to interferon unresponsiveness ( 10 ) . interestingly , experimental work raised the possibility that il-8 may not only act as a mere chemoattractant protein in the liver , but also exerts direct profibrogenic functions . however , direct isolated il-8 effects on hepatic tissues have not yet been sufficiently elucidated . the aim of the present study was to investigate the effects of intramuscular il-8 injection on hepatic tissues in an in vivo histopathological animal model . this randomized , controlled , single - blinded interventional study was approved by the animal ethics committee ( reference number : 2011/16 ) and was conducted in accordance with the  animal welfare act and the guide for the care and use of laboratory animals ( nih publication no . twelve new zealand white rabbits obtained from the laboratory animal production unit were used . before surgery , rats were kept in the laboratory for 1 week in a temperature  ( 222c ) and humidity  ( 505% ) controlled room for acclimatization with exposure to 12 hours of light and 12 hours of darkness . the rats were given only water during the 12 hours before start of the procedures . 1 gluteus maximus muscle was injected daily with 1 mcg / kg ( the dosages were standardized according to previous studies ) of il-8 ( biovision recombinant human endothelial il-8 , cat . number 4149 - 25 ) in 6 rabbits ( group a ) . the remaining 6 rabbits ( to determine to normal porto - hepatic morphology of the rabbit genus ) were in the sham group ( group b ) . at the end of the 7 day the harvested specimens were fixed in 10% formaldehyde solution for 48 hours , routinely processed , and embedded in paraffin . slices of 4 m thickness were obtained from paraffin blocks and put onto polylysine - coated slides . one of the slices was stained with hematoxylin - eosin ( h&e ) and the other was stained with masson s trichrome . microscopically , regional tissues were scored according to portal inflammation , focal necrosis , piecemeal necrosis , and total impact . for every experimental animal , median values of the scores generated by 2 pathologists the native histopathologic microscopic view of the portal area and varied scores of damaged hepatic areas are provided in figure 1 . data were analyzed using the statistical package for social sciences ( spss ) software ( version 10.0 for windows ) . all differences associated with a chance probability of 0.05 or less were considered statistically significant . the percentages of necrosis score values for the 3 groups were compared using pearson s correlation test . this randomized , controlled , single - blinded interventional study was approved by the animal ethics committee ( reference number : 2011/16 ) and was conducted in accordance with the  animal welfare act and the guide for the care and use of laboratory animals ( nih publication no . twelve new zealand white rabbits obtained from the laboratory animal production unit were used . before surgery , rats were kept in the laboratory for 1 week in a temperature  ( 222c ) and humidity  ( 505% ) controlled room for acclimatization with exposure to 12 hours of light and 12 hours of darkness . the rats were given only water during the 12 hours before start of the procedures . 1 gluteus maximus muscle was injected daily with 1 mcg / kg ( the dosages were standardized according to previous studies ) of il-8 ( biovision recombinant human endothelial il-8 , cat . number 4149 - 25 ) in 6 rabbits ( group a ) . the remaining 6 rabbits ( to determine to normal porto - hepatic morphology of the rabbit genus ) were in the sham group ( group b ) . at the end of the 7 day the harvested specimens were fixed in 10% formaldehyde solution for 48 hours , routinely processed , and embedded in paraffin . slices of 4 m thickness were obtained from paraffin blocks and put onto polylysine - coated slides . one of the slices was stained with hematoxylin - eosin ( h&e ) and the other was stained with masson s trichrome . microscopically , regional tissues were scored according to portal inflammation , focal necrosis , piecemeal necrosis , and total impact . for every experimental animal , median values of the scores generated by 2 pathologists the native histopathologic microscopic view of the portal area and varied scores of damaged hepatic areas are provided in figure 1 . data were analyzed using the statistical package for social sciences ( spss ) software ( version 10.0 for windows ) . all differences associated with a chance probability of 0.05 or less were considered statistically significant . the percentages of necrosis score values for the 3 groups were compared using pearson s correlation test . the obtained scores of portal inflammation , focal necrosis , piecemeal necrosis , and total impact were presented as mean  standard deviation ( sd ) in each group . total impact score , portal inflammation , focal necrosis , and piecemeal necrosis were the histopathologic changes present in a higher incidence in the il-8 group compared with the control group . the obtained scores are summarized in table 2 . the total impact scores ( 5.671.51 vs. 2.670.82 ) , portal inflammation scores ( 2.671.03 vs. 1.170.41 ) , focal necrosis scores ( 2.000.63 vs. 1.170.41 ) , and piecemeal necrosis scores ( 1.000.00 vs. 0.330.52 ) were markedly higher in the il-8 group . the differences were significant when the groups were compared according to total impact score , portal inflammation , focal necrosis , and piecemeal necrosis according to pearson s correlation ( p<0.05 ) . the most significant differences were detected at the total impact scores ( p=0.002 ) and the portal inflammation scores ( p=0.008 ) . il-8 , a member of the chemokine family , has been identified as a neutrophil chemotactic polypeptide in the conditioned media of lipopolysaccharide - stimulated peripheral blood monocytes . the protein , consisting of 72 amino acids in its mature form , is identified as a basic and heparin - binding protein . il-8 also exhibits chemotactic activities against t lymphocytes and basophils , as well as neutrophils in vitro . il-8 production has also been observed in vitro in a wide variety of cells , including monocytes , t lymphocytes , neutrophils , vascular endothelial cells , dermal fibroblasts , keratinocytes , hepatocytes , and human gastric cancer cells . high il-8 levels in the liver and the circulation have been found in patients with acute liver injury , such as alcoholic hepatitis or ischemia - reperfusion injury . these conditions are clearly associated with neutrophil - mediated tissue damage , but less is known about the involvement of il-8 and/or neutrophils in chronic liver injury . reports in the literature have indicated that il-8 may have many harmful impacts . in particular , it was claimed that il-8 has an important role in many hepatic disorders induced by varied agents . il-8 had been functionally linked to hepatic neutrophil infiltration and liver inflammation , and to activation of profibrogenic , collagen - producing hepatic stellate cells [ 1418 ] . nobili et al suggested that il-8 was responsible for portal inflammation in patients with chronic liver disease and found that serum il-8 levels were elevated in patients with neonatal hepatitis . zimmermann et al reported that il-8 has a novel role in recruitment and activation of hepatic macrophages in chronic liver disease . declared that alcoholic hepatitis involved elevated tumor necrosis factor alpha and il-8 plasma and tissue levels . additionally , purohit et al noted that mortality was related with the serum concentrations of certain cytokines , including tumor necrosis factor alpha , il-6 , and il-8 , in hospitalized patients with alcoholic hepatitis . investigated the effect of il-8 in patients with chronic hepatitis c and reported that increased il-8 production may be related with malignant transformation of hepatocytes . another trial , investigating carbon tetrachloride induced hepatotoxicity , reported that  carbon tetrachloride causes a rapid increase in il-8 mrna expression in labeled poly a+ rna from cultured human hepatoma cells and this increase correlates with a later and significant increase in the levels of il-8 protein  . additionally , james et al claimed that elevated il-8 level was predictive of hepatocellular injury caused by acetaminophen hepatotoxicity in children and adults . similar published studies have found many more cytokines in hepatotoxicity by separate or combined impact . however , there was not sufficient data to establish the isolated effect of il-8 in hepatic tissues . in the present study , we aimed to reveal the hepatic impacts of isolated il-8 injection in a rabbit model . the knodell histology activity index ( hai ) , published in 1981 , was the first system of its type and is widely regarded as the benchmark for objective , semiquantitative , reproducible description of the various morphological lesions of chronic hepatitis . since publication of the knodell hai , systems for grading and staging incorporate the view that necroinflammation is not only a measure of severity but also of ongoing disease activity and is the parameter most potentially responsive to therapy . the lesions of fibrosis and parenchymal or vascular remodeling are referred to as  stage  and indicate long - term disease progression . grade may fluctuate with disease activity or therapeutic intervention ; stage is considered relatively constant . all systems report grade and stage , although they may arrive at a score using different criteria . the differences are subtle but potentially important when comparing clinical studies that have used 2 different systems . ishak s 1994 review promotes the use of descriptive terminology for activity and fibrosis , rating the different elements of activity as either present or absent ; when present , a degree of severity is stated . finally , a recent modification of the knodell hai , commonly referred to as the ishak system , provides consecutive scores for well - defined lesions within 4 separate categories , which are added together for the activity grade   ( table 1 ) . in the present study , portal inflammation showed higher statistical significance between il-8 injected rabbits and the control group ( p=0.008 ) . moreover , focal necrosis ( p=0.022 ) , piecemeal necrosis ( p=0.010 ) , and total impact ( p=0.002 ) were significantly higher in intramuscular il-8  injected rabbits . there are 2 limitations that need to be acknowledged and addressed regarding the present study . it can be assumed that the dose of il-8 injection used in the study is toxic . however , il-8 injection is not a currently used method . we conducted one of the few studies in the literature that focused on investigating the angioneogenic effect of il-8 administered intramuscularly in rats , and concluded that daily administration at a dose of around 1 mcg / kg caused local tissue necrosis . however , duration of repeat doses and safety dosage ranges must be clarified by further investigations . the current treatment strategies were focused on preventing these harmful hepatic inflammatory responses . however , the therapeutic target has not yet been defined .
backgroundthe aim of this study was to investigate the effects of intramuscular il-8 injection on hepatic tissues using an in vivo histopathological animal model.material/methodstwelve new zealand white rabbits were used for this randomized , controlled , single - blinded interventional study . for 6 days , 
 1 gluteus maximus muscle was injected daily with 1 mcg / kg of il-8 in 6 rabbits ( group a ) . 
 the remaining 6 rabbits ( to determine to normal porto - hepatic morphology of the rabbit genus ) were in the sham group ( group b ) . at the end of the 7th day 
 , all rabbits were killed and livers were meticulously harvested . 
 microscopically , regional tissues were scored according to portal inflammation , focal necrosis , piecemeal necrosis , and total impact.resultstotal impact score , portal inflammation , focal necrosis , and piecemeal necrosis were the histopathologic changes present in a higher incidence in the il-8 group compared with the control group . 
 the differences were significant when the groups were compared according to total impact score , portal inflammation , focal necrosis , and piecemeal necrosis according to pearson s correlation ( p<0.05 ) . 
 the most significant differences were detected at the total impact scores ( p=0.002 ) and the portal inflammation scores ( p=0.008).conclusionsour results showed that il-8 may damage hepatocytes . 
 this can be the determined target for new therapeutic strategies . 
 further trials should be designed to obtain definitive results .