Effects of brief exposure to high temperatures on HSP70 expression in oogenesis of Calliptamus italicus

The expression of heat shock protein 70 (HSP70) in the oogenesis of Calliptamus italicus was detected by immunohistochemistry after the exposure of adult insects to temperatures of 33, 36, 39, and 42 ℃ for 4 h. The results showed that HSP70 was expressed in the oocytes and follicular cells during the previtellogenic stage, but was only expressed in the follicular cells only during the vitellogenic and postvitellogenic stages. The relative expression of HSP70 showed an initial increase, but then decreased with an increase in temperature in the range from 33~42 ℃. The highest expression, which was significantly higher than those in the control (27 ℃), was observed when adult insects were exposed to 36 ℃ (P<0.05). The lowest expression was observed when adults were exposed to 42 ℃, but there was no significant difference between treatment at 42 and 27 ℃ (P>0.05). The relative expression of HSP70 was significantly different at different temperatures, which may be critical for the resistance and adaptation of C. italicus to brief exposure to high temperature.