Male Sprague-Dawley rats (270–320 g, Daehan Animal, Seoul, Korea) were used for this study. All rats had free access to food and water and were maintained on a 12 hr light-dark cycle. All procedures were approved by the Institutional Animal Care and Use Committee at the Daegu Haany University and conducted in accordance with National Institutes of Health guidelines for the care and use of laboratory animals. Each group consisted of 6–8 rats, unless stated otherwise.