Abstract: The experiment was aimed at the effect of Dioxin on AhR and the protective effect of free radical scavenger (FRS) in the liver. Seventy-two rats were randomly divided into three groups: the control group (groupⅠ)， Dioxin treatment group (groupⅡ) and GC + Dioxin treatment group (group Ⅲ). GC was used to study the antagonistic effects of Dioxin. After four， eight， twelve and eighteen days blood and liver samples were taken. Compared with control group, the Dioxin group the SOD significantly decrease (P<0.01), and the MDA levels significantly increased (P<0.01). The result of the immunohistochemical examination with AhR exhibited that the AhR decrease markedly (P<0.05) at 4-day age and increase obviously at 8 day age (P>0.05) and at the 12, 16-day age (P<0.01). On the other hand, compared with Dioxins groups GC groups can inhibit the decreasing and increasing (P<0.05). These results indicated that Dioxin could down-regulate the AhR at first and than up-regulate it in the other days. In the nuclear， the Dioxins group increase obviously (P<0.01) at the 4, 8, 12, 16-day age compared with control group. Then compared with Dioxin groups GC groups can inhibit the increasing (P<0.05). The results showed that rat Dioxin poisoning can impact the quantity of AhR, and enduce various kinds poisoning effects. GC has significant protective effect on injuries of Dioxin in the liver.

Key words: Dioxin; AhR; free radical; protective effect