  The mesonic quantum fluctuations and their corrections on the chiral
condensate and pion polarization function are investigated in the
self-consistent scheme of SU(2) Nambu-Jona-Lasinio model by exactly calculating
the next-to-leading order (NLO) Feynman diagrams in $1/N_c$ expansion. While
the fluctuations and corrections depend strongly on the meson's three-momentum
cut-off $\Lambda_M$, no chiral symmetry restoration is found since the
cancellation between the NLO and the one-quark-loop diagram with quark mass
deviated from the mean-field value.
