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Damage to the small intestine secondary to heat stroke is a major factor in heat stroke-related morbidity and mortality. However, the underlying mechanisms by which heat stroke causes small intestinal lesions and dysfunction remain unclear. To explore the pathogenesis of small intestinal tissue and epithelial cell injury, the SW480 cell heat stress model and the mice heat stroke model were established to mimic heat stroke. Morphologic changes in intestinal tissue and increased TUNEL-positive index were induced by heat stress in vivo. Heat stress activated the lysosomal-mitochondrial apoptotic pathway in SW480 cells, increasing intracellular reactive oxygen species and causing lysosomal membrane permeabilization with subsequent release of cathepsin B to the cytosol, mitochondrial depolarization, and cytochrome C release to cytosol. An increase in the Bax/Bcl2 ratio, caspase-9 and caspase-3 were observed. N-Acetyl-L-Cysteine was shown to inhibit ROS generation, suppress permeabilization of lysosomal membranes, decrease levels of cathepsin B and cytochrome C in the cytosol, and inhibit Bax/Bcl2 ratio, caspase-9 and caspase-3 activity both in vitro and in vivo. Mitochondrial damage was alleviated when the models were pre-treated with CA-074 Me both in vitro and in vivo, decreasing cathepsin B and cytochrome C levels in the cytosol, Bax/Bcl2 ratio, caspase-9 and caspase-3 activity. In our models, heat stress-induced apoptosis of small intestinal tissue and epithelial cells through accumulation of ROS and activation of the lysosomal-mitochondrial apoptotic pathway involved the release of cathepsin B. These findings may offer potentially pharmaceutical targets and strategies to repair intestinal injury caused by heat stroke.

Eclipta prostrata (EP) is often prescribed in combination with glucocorticoid to treat glomerular nephritis, nephrotic syndrome, and IgA nephropathy in clinical practice of Traditional Chinese Medicine. Previous studies from our laboratory revealed that coadministration of EP significantly increased the plasma concentration of prednisolone while decreased the level of cotreated prednisone in rats. However, the underlying mechanism remains unclear. 11 β -Hydroxysteroid dehydrogenase (11 β -HSD) belongs to the family of oxidoreductases that catalyze the interconversion of prednisone to active prednisolone. Therefore, the current study aimed to investigate the effects of EP on the activity and expression of 11 β -HSD in rat liver and kidney. The results showed that oral administration of EP significantly increased the activity of 11 β -HSD I in the liver and 11 β -HSD II in the kidney by employing the microsomal incubation system. Moreover, gene and protein expressions of 11 β -HSD I and 11 β -HSD II were also increased in rat liver and kidney, respectively. These results suggest that the effects of EP on 11 β -HSD may attribute to the mechanism that administration of EP improves the efficacy and reduces adverse drug reactions of glucocorticoid in patients undergoing combinational therapy.