The laboratory conditions in the study room were controlled and monitored by
an automatic system. Animals were housed in standard cages with sawdust bedding
or polypropylene grid cages, with a controlled 12-h light/dark cycle. Temperature
was maintained at 19 C to 25 C with a relative humidity of 30% to 55% and
an air exchange rate of 15 times per hour. Potable water and standardized diet were
provided ad libitum.