Seventy-five adult male Sprague Dawley rats were randomized into five groups : ( @ ) SBI + drug vehicle ( peanut oil , @ml kg ( -@ ) ) ; ( @ ) SBI + DEXA ( @mg kg ( -@ ) ) ; ( @ ) SBI + low-dose PRO ( @mg kg ( -@ ) ) ; ( @ ) SBI + high-dose PRO ( @mg kg ( -@ ) ) ; and ( @ ) sham SBI + drug vehicle .