The role of phosphokinase Czeta in the anterior cingulate cortex in the emotional response of rats with inflammatory pain induced by Freund’s safe adjuvant

  OBJECTIVE: To observe the emotional response of CFA-induced inflammatory pain model rats, and to explore the relationship between the anterior cingulate cortex (ACC) phosphokinase Zeta (PKCzeta) and the emotional response of inflammatory pain rats.

  Method: 24 clean male SD rats were randomly divided into blank control group and model control group. The model of chronic inflammatory pain was established by subcutaneous injection of Freund's complete adjuvant. Observe the changes in body weight and pain threshold of each group of rats before modeling (base) and 3, 7, 14, 21, and 28 days after modeling; observe all rats in elevated O maze at 14, 21, 28 days after modeling Total movement distance, open arm movement distance, open arm entry times, and open arm residence time percentage in. Observe the total movement distance of all rats in the open field, the movement distance of the central quadrant, the number of entrances to the central quadrant, and the residence time of the central quadrant on the 14th and 29th days after modeling. Western blotting was used to detect the expression of PKCzeta protein in the ACC region of the contralateral and affected side 14 and 29 days after modeling.

  Result: There was no significant difference in body weight between the two groups of rats at each time point (P>0.05). Before modeling, there was no significant difference in pain threshold between the two groups of rats (P>0.05); 1 day after modeling, the pain threshold of the model control group was significantly reduced (P<0.05), and it was significantly lower throughout the experiment In the blank control group (P<0.05). Compared with the blank control group, the open arm movement distance and open arm residence time percentage of the model control group decreased significantly at 28 days after the model (P<0.05), and the central quadrant movement distance and the number of central quadrant entry times were significantly reduced at 29 days after the model. (P<0.05). 29 days after modeling, the expression of PKCzeta protein in the affected ACC area of the model control group was significantly higher than that of the blank control group (P<0.05). And open arm movement distance, open arm residence time percentage, central quadrant movement distance, central quadrant entry times were negatively correlated with changes in PKCzeta protein expression on the affected side.

  Conclusion: CFA-induced chronic inflammatory pain rats can show abnormal emotional behavior; chronic inflammatory pain emotional behavior may be related to the high expression of PKCzeta in the ACC area.