One-shot delayed-type hypersensitivity reaction in the mouse liver causes a sustained liver injury to picryl chloride

The developmental characteristics of liver injury induced by a delayed-type hypersensitivity (DTH) mechanism against picryl chloride were examined for 9 consecutive weeks in 3 mouse strains, BALB/c, Kunming and ICR mice. The changes of most biochemical parameters were similar in these three strains, namely, the activities of serum transaminases, lactic dehydrogenase, and prolidase were elevated significantly on day 1, during the first several weeks, and almost throughout the duration, respectively, of liver injury. The content of liver hydroxyproline was also increased after 1-9 weeks of liver injury. In addition, a significant decrease of liver weight, serum alkaline phosphatase and albumin level was observed in BALB/c and Kunming mice. Similar changes in liver histology were also found in the three strains. The hepatocellular necrosis and inflammatory infiltration into the portal area were the predominant features on day 1 and were still distinct during the subsequent several weeks. The mild or moderate hepatocellular degeneration, regeneration and connective tissue hyperplasia were observed after 1 or 3 weeks. A bridging necrosis between portal and portal was observed in several BALB/c and ICR mice, reflecting the possibility of exacerbation of liver injury. These results suggest that the liver injury could be caused and sustained by a one-shot DTH reaction to picryl chloride. The chronicity of the biochemical and histopathological characteristics may be helpful in elucidating the mechanisms of chronic development of liver injury.