Figure 6

A model describing the macrophage response during the caudal fin regeneration of zebrafish larvae infected with M. marinum. (A) Infection and amputation experiment design. Injection of low, moderate and high doses of M. marinum in the caudal vein at 30 hpf then amputation of the caudal fin at 72 hpf. (B) Schematic representation of the mycobacteria dose effect on the macrophage response. The low dose accelerated the macrophage response from 1 hpA as revealed by the more rapid macrophage recruitment and alignment at the fin tip. The moderate dose triggered more granuloma formation and necrosis of macrophages leading to a decreased inflammatory response at 72 hpA. The high dose also caused more granuloma formation, necrosis of macrophages resulting in the absence of macrophage response at 72 hpA. (C) Schematic representation of the mycobacteria dose effects on the caudal fin regrowth. The regeneration process was accelerated with the low dose, decreased with the moderate dose and completely lost with the high dose.