  We study the effect of the chiral symmetry restoration (CSR) on heavy-ion
collisions observables in the energy range $\sqrt{s_{NN}}$=3-20 GeV within the
Parton-Hadron-String Dynamics (PHSD) transport approach. The PHSD includes the
deconfinement phase transition as well as essential aspects of CSR in the dense
and hot hadronic medium, which are incorporated in the Schwinger mechanism for
the hadronic particle production. We adopt different parametrizations of the
nuclear equation of state from the non-linear $\sigma-\omega$ model, which
enter in the computation of the quark scalar density for the CSR mechanism, in
order to estimate the uncertainty in our calculations.
