  We investigate the suppression of $\pi^0$-spectrum in a wide range of
$p_\perp$ up 60 GeV/c which is caused by the energy loss of the gluon and quark
jets in quark-gluon plasma. The physical characteristics of initial and mixed
phases were found in the effective quasiparticle model by analogy with previous
work \cite{5}. The PHENIX data up 10 GeV/c within the limits of precision are
described by quasiparticle model with decrease of the thermal gluon mass and
effective coupling in the region of phase transitin (at $T\to T_c$ from above).
We also take into account the intrinsic transverse momentum $k_\perp$ of
partons.
  The suppression factor $R_{AA}(p_\perp)$ shows the weak rise with increase of
$p_\perp$ above 4 GeV/c, then it reaches smooth maximum at $p_\perp \sim 20$
GeV/c and then decrease at $p_\perp\sim 60$ GeV/c again to value $R_{AA}$ at
$p_\perp\simeq$ 4 GeV/c. The factor $R_{AA}$ in this range of $p_\perp$ is
changihg weakly if intrinsic momentum $k_\perp$ is taken into account.
