OBJECTIVETo investigate the effect of voluntary exercise on the proliferation and differentiation of hypothalamus progenitor cells in adult rats.

METHODSMale Wistar rats were divided into voluntary exercise (EX) and sedentary (SE) groups, both of which were further divided into 6 subgroups for observation on days 6, 13, 23, 33, 43 and 53. Bromodeoxyuridine (BrdU) was intraperitoneally injected daily for 5 consecutive days after commencing voluntary exercise, and at the specified time points during voluntary exercise, the rats' brains were removed to observe the numbers of BrdU-positive cells in the hypothalamus.

RESULTSImmunohistochemical analysis showed that the numbers of BrdU-positive cells in the hypothalamus of EX subgroups were significantly greater than those of SE subgroups on days 23, 33, 43 and 53. In EX group, the number of BrdU-positive cells double-stained for a mature neuron marker increased after 43 days of voluntary exercise, which did not occur in SE group.

CONCLUSIONLong-term voluntary exercise can promote the proliferation of neuronal progenitor cells in the hypothalamus and their differentiation into neurons.

Animals ; Cell Differentiation ; Cell Proliferation ; Hypothalamus ; cytology ; Male ; Neurons ; cytology ; Physical Conditioning, Animal ; Rats ; Rats, Wistar ; Stem Cells ; cytology

OBJECTIVETo investigate the effect of acute heat stress on the day-night circadian gene Per2 mRNA expression in the liver of rats.

METHODSMale Wistar rats were randomly divided into two groups and exposed to heat at 32 degrees celsius; or to a room temperature at 24 degrees celsius; (control). After 7 days of heat exposure, the body temperature was measured by telemetry. The relative weight of the pituitary and adrenal glands was determined after the exposure, and liver Per2 mRNA expression level was detected using RT-PCR.

RESULTSAcute heat stress did not obviously affect body temperature or body weight of the rats. Seven days of heat exposure increased the relative weight of the pituitary and adrenal glands and significantly lowered Per2 mRNA expression level at night.

CONCLUSIONAcute heat stress can interfere with the day-night circadian gene Per2 mRNA expression in rats.

Adrenal Glands ; Animals ; Body Temperature ; Body Weight ; Heat-Shock Response ; genetics ; Liver ; metabolism ; Male ; Organ Size ; Period Circadian Proteins ; genetics ; metabolism ; Pituitary Gland ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar