In a nonstick frying pan, heat the olive oil over medium-high and cook the chicken strips about 5 minutes or until the chicken is lightly browned and no longer pink. Add the diced eggplant, onion, peppers, tomatoes, reserved tomato juice, celery, and mushrooms to the chicken, reduce the heat, and simmer about 10 minutes or until the vegetables are tender. Add the bread crumbs and black pepper and add half the mixture into each eggplant shell.