Objective To prepare
mouse model with
heat stress and determine its pathological changes of the
lung and
brain during
heat stress.
Methods BALB/c
mouse were randomly (random number) divided into two
groups, control group and
heat stress group. The
animals in the
control group were sham- heated at a
temperature of ( 25 ± 0.5) ℃ and
humidity of (35 ± 5 ) %. The
animals of
heat stress group were placed in a prewarmed
incubator maintained at (35.5 ± 0.5) ℃ and relative
humidity of (60 ± 5) %. Rectal
temperature (Tc) was monitored, and when Tc respectively reached 39 ℃, 40 ℃ , 41 ℃ and 42 ℃, those study
animals were killed. The other
animals were removed from the
incubator and allowed to cool at an ambient
temperature of (25 ±0. 5)℃ and
humidity of (35 ±5)% , respectirvely for 12 and 24 hrs when Tc reached 41 ℃ , and for 6 hrs when Tc reached 42 ℃. The
lung and
brain of all the
animals were isolated.
Hematoxylin and
eosin stain and
light microscope were used to detect their pathological changes. Results All the
animals displayed
uniform response to the
heat stress. Low degree of
heat stress could induced obviously pathological changes of the
lung, progressively greater damage to
lung with further congestion of
lung matrix, asystematic
hemorrhage of alveolar space, abscission of
alveolar epithelial cell and disappear of
pulmonary alveolus tissue structure were detected with the rise of Tc to 42 ℃. However,
absorption of congestion and
hemorrhage and recovery of
pulmonary alveolus tissue structure could also be seen with
cooling at ambient
temperature. With low degree of
heat stress, the
brain only showed moderate
edema. Neuronal denaturation and
necrosis were detected when Tc reached to 42 ℃. Interestingly, the lesions of
brain further aggravated even through
cooling treatment after Tc reached to 42 ℃ , but recovery could been observed after
cooling treatment followed with Tc of 41 ℃. Conclusions The pathological changes of the
lung and
brain showed distinctive lesions to
heat stress and
cooling treatment, and these changes were correlated with the timing and
time of
cooling treatment, which provide the experimental basis to further study the mechanisms between the
heatstroke and
multiple organ dysfunction syndrome (
MODS).