A mechanical sliding sleeve (101) includes a sleeve housing (105) defining a fluid communication port, a first sub (103) affixed to the sleeve housing, and a second sub (107) affixed to the sleeve housing. An isolation sleeve (201) is disposed in an internal bore defined by the sleeve housing, the first sub, and the second sub, and defines a fluid communication port (113). The isolation sleeve is slidable along interfaces between the first sub, the second sub, and the sleeve housing between an open position, wherein fluid is allowed through the ports, and a closed position, wherein fluid passage through the ports is inhibited. A sealing element is operably associated with the sleeve housing, the first sub, the second sub, and the isolation sleeve to inhibit fluid flow through the ports unless the isolation sleeve is in the open position, and to seal at least a portion of the interfaces from contact with downhole fluids.