Ohio won the Mid-American Conference wrestling championship last season.    But repeating will be a difficult chore after Ohio lost four conference placewinners from last year's team.    Junior Luke Moore, the defending league champion at 174 pounds, is an All-American candidate for the Bobcats.    Teammate Ryan Smith, second in the MAC, also has national tournament experience at 157. hio also expects to rely on Mark Shrout at 184.    The Bobcats were 14-6 in duals, including 3-2 in the league, before winning the MAC tournament a year ago.    Expect Central Michigan to make a strong run at regaining its spot atop the league standings.    The Chippewas bring back national qualifiers Jordan Webster (133), Jason Mester (141) and Ty Morgan (149). Mester and Morgan won conference titles last season.    Kevin Carr should be more effective for Central Michigan this year as he moves down a weight to 165.    Buffalo loses three national qualifiers, but has a talented young corps of returning wrestlers.    David Guarino returns for the Bulls at 165 after wrestling in the national tournament last season.    Kent State, third in the MAC last year, appears strongest in the upper weight classes.    Nick Nemeth is back at 165 for the Golden Flashes after finishing second in the MAC.    Scott Owen of Northern Illinois will return to defend his league championship at 157. Owen was only one win shy of becoming an All-American last season before losing 5-4 to former NCAA champ Kirk White of Boise State.    The Huskies hope to improve after finishing fifth at the MAC championships last season.    Eastern Michigan struggled to a last-place finish in the MAC last year under first-year coach Charlie Branch.    The Eagles will be led this year by juniors Tim Hoff (165) and Travis Kraft (184). Senior Darnell Ruffin (141) also has shown improvement.