The relationship between small heat shock proteins and redox homeostasis during acute heat stress in chickens

As heat stress is a major emerging issue in poultry farming, investigations on the molecular mechanisms of the heat-triggered cellular response in chickens are of special importance. In the present study, 32-day-old Ross 308 broiler chickens were subjected to 37 degrees C environmental temperature combined with 50% relative humidity for 4 or 8 h respectively. Following sampling, redox parameters such as malondialdehyde (MDA), reduced glutathione (GSH), protein carbonyl levels as well as glutathione pemxidase activity were assessed in liver, spleen, and kidney homogenates. The concentrations of small heat shock proteins (sHSP-s) HSP27, alpha A- and alpha B-crystallins were also investigated. Among these organs, the liver was found the most susceptible to heat-provoked oxidative stress, indicated by enhanced lipid peroxidation and rapid activation of protective pathways, including the definite increase of glutathione peroxidase activity and the excessive utilization of (alpha A- and alpha B-crystallin proteins. Heat-associated decline of protein carbonylation and GSH content was observed in the liver in correlation with the increased involvement of (alpha A- and alpha B-crystallins in cellular defense, resulting supposedly in an over-compensation mechanism. These data highlight the hepatic sensitivity to acute heat shock, potential adaptation mechanisms, and the specific role of sHSP-s in the restoration of physiologic cell function.

Automated summary

The liver was found to be the most susceptible to heat-provoked oxidative stress, with rapid activation of protective pathways and the involvement of sHSP-s leading to an over-compensation mechanism.