  We study dynamically generated $a_0$ resonances by interactions between
vector mesons including their coupling to channels of pseudoscalar mesons
within coupled-channel approach. Both vector and pseudoscalar mesons are
considered as $t$-channel exchanged mesons for calculating interactions between
vector mesons. Analogous to $a_0(980)$ as a $K\bar K-\pi\eta$ dynamically
generated state, there is an $a_0(1710)$ as a coupled channel dynamically
generated state near $K^*\bar{K}^*$ threshold. The channels involved are
$\rho\phi,K^*\bar{K}^*,\rho\omega, K\bar{K},\pi\eta$. This $a_0$ mainly decays
to $\rho\omega$, $\pi\eta$ and $K\bar{K}$. This pole is much tied to the
coupled channel effect. If we turn off either $\rho\phi$ or $K^*\bar{K}^*$, the
pole disappears. In addition, it is found that $a_0(1450)$ may also be
dynamically generated by $\rho\omega$ interactions due to $\pi$ and $\eta$
exchange.
