Immunolocalization of CD3, CD5 and MHCII in amputated tail and limb of the lizard Podarcis muralis marks a scarring healing program

Abstract

The effect of inflammation on tail and limb amputation in lizards is believed to inhibit regeneration. In support of previous studies, the present experimental and immunohistochemical analysis has detected some markers (CD3, CD5, MHCII) of mammalian T-lymphocytes and macrophages of inflammatory type in three different conditions where inflammation is activated. Bioinformatics comparisons indicate that the employed antibodies cross-react with lizard cells. While in regenerating tails few or no immune cells are seen, in microbial-infected and non-regenerating tails, a massive infiltration of mast cells, sparse macrophages and T-lymphocytes is present. In healing limbs, immunolabelled cells likely represented by macrophages and lymphocytes remain in healing tissues of the stump for 2–3 weeks. In the regenerating blastema after heat cauterization of the apical region, a massive infiltration of mast cells and granulocytes occurs at 1–3 days post-injury and a scarring outgrowth is later formed. Although the three markers appear not discriminate the types of immune-cells in lizard, they confirms that immunolabelled cells expressing markers of inflammation are produced in large number in the tail or limbs with strong inflammatory condition. Coupled with previous studies, the present observations support the idea that a high inflammation attracting numerous mast-cells, inflammatory macrophages and T-lymphocyte inhibits regeneration.