Curcumin attenuates the effects of transport stress on serum cortisol concentration, hippocampal NO production, and BDNF expression in the pig

Curcumin, the active component of curcuma longa, has been reported to be effective in alleviating chronic stress-induced disorders in rodents by modulating neuroprotection and neuroendocrine functions of the central nervous system, especially hippocampus. However, it is unclear whether curcumin can attenuate the subacute stress response induced by 2 h of road transport in the pig. Therefore, the present study was designed to identify the changes of serum cortisol concentration, hippocampal nitric oxide (NO) production, and related gene expression in response to 2 h of transport and to explore whether curcumin treatment (8 mg/kg, p.o.) for 21 d before transport may alleviate the stress-induced responses in the hippocampus of pigs. We found that 2 h of transport elevated serum cortisol concentration (P < 0.01), increased hippocampal NO content, and reduced brain-derived neurotrophic factor (BDNF) mRNA expression in pigs not treated with curcumin, whereas these stress responses were all reversed or attenuated in curcumin-treated pigs. In addition, the stress-induced increase in the expression of constitutive nitric oxide synthase (cNOS) and enzyme activities of total NOS, cNOS, and inducible NOS (iNOS) was also reversed or attenuated in curcumin-treated pigs. However, neither transport nor curcumin caused significant alterations in hippocampal expression of 11β-hydroxysteroid dehydrogenase type 1 and type 2 (11β-HSD1 and 2), glucocorticoid and mineralocorticoid receptors (GR and MR), or pro-/anti-apoptotic molecules (Bax-α and Bcl-xL). These results suggest that curcumin can alleviate subacute stress response in pigs through its neuroprotective effects on modulating hippocampal NO production and BDNF expression.