A NEW STRATEGY FOR REGULATING THE IMMUNOLOGICAL LIVER-INJURY - EFFECTIVENESS OF DTH-INHIBITING AGENTS ON DTH-INDUCED LIVER-INJURY TO PICRYLCHLORIDE

Aqueous extracts from various crude drugs showing a selective inhibiti on on the induction or effector phase of delayed-type hypersensitivity (DTH) reaction were applied to the new model of liver injury induced in mice by picryl chloride(PCl)-induced DTH. The inhibiting drugs to t he induction phase of DTH, Fructus Triburi (FT) and Er-Miao-San (EMS), showed a remarkable improvement against the elevation in serum transa minase levels as well as in histopathological changes when given durin g this phase. The administration in the effector phase by Rhizoma Smil acis Glabrae (RSG) and Cortex Dictamni (CD), selectively inhibiting th e phase of DTH, also significantly improved the liver damage. In addit ion, RSG and CD showed an almost complete recovery of serum alkaline p hosphatase from a persistent decrease in the sustaining process of liv er injury when given consecutively for 4 weeks after the elicitation o f liver injury. Cyclophosphamide, an immunosuppressive agent, signific antly inhibited the enzymatic elevation given in either phase, while i t did not affect the ability to sustain liver injury. When the above e xtracts were given in a combined manner to the same mouse during these two phases, respectively, FT with RSG and EMS with CD showed a distin ct synergism against the liver injury. RSG or CD also enhanced the act ivity of prednisolone in suppressing PCl-induced ear contact sensitivi ty. These findings suggest that this immunological liver injury may be regulated by a set of selective suppressants to DTH reaction and the suitable application of such agents may pave the way for a new strateg y inn treating liver damage. (C) 1997 The Italian Pharmacological Soci ety.