Chemically induced liver regeneration is characterized by specific IL-6 gene expression

IL-6 and TNFα have been shown as important cytokines in liver regeneration induced in partially hepatectomized rats. Nonetheless, IL-6 gene expression in the course of chemically induced hepatic regeneration, resembling what occurs in humans infected by hepatitis virus in acute manner, remains obscure. To gain an insight on this matter we determined IL-6 and TNFα gene expression in Wistar rats after acute and chronic liver intoxication with CCl4 and/or turpentine. We used a semiquantitative method of RT-PCR to analyze cytokine gene expression and, quite interestingly, IL-6 was detected only at 24 h after acute damage as opposed to TNFα expression that was increased from 6 to 48 h after acute injury. A single intradermally- injected dose of turpentine did not suffice to induce IL-6 gene expression at any studied times, but, as expected, turpentine-treated animals showed decreased albumin mRNA transcripts as compared with the control rats. Furthermore, livers from cirrhotic animals did not show detectable IL-6 gene transcripts, but, IL-6 expression re-appeared in cirrhotic rats treated with an additional acute CCl4 dose, indicating that IL-6 is a critical component of the brisk regenerative response induced by CCl4