Gossip is very contagious. It takes over the culture of an organization similar to how an aggressive communicable disease spreads through a population. As a leader, you must avoid engaging in gossip. Similarly, gently encourage others not to participate in starting and spreading gossip throughout the organization. Gossip is rarely about anything positive. Gossip is bad for organizational culture and morale; leads to a divisive culture and the formation of "cliques" in the workplace; and weakens trust, partnerships, and collaborations within the organization.
Remember that your colleagues and team members constantly observe you and your behavior. As a leader, your behavior sets the norm and standard for the organization. Therefore, model the behavior you wish others to adopt.