Sprague-Dawley rats were randomly assigned to a normal group ( n = @ ) , an IgAN model group ( n = @ ) , a prednisone treatment IgAN group ( n = @ ) , a @,@-dihydroxyvitamin D@ IgAN group ( n = @ ) , and prednisone plus @,@-dihydroxyvitamin D@ treatment group ( n = @ ) .