[The expression of protein kinase C and the regulatory effect of nerve growth factor in the lung and the visceral sensory afferent system of asthmatic guinea pigs].

Objective: To explore the expression of protein kinase C (PKC) and the regulatory effect of nerve growth factor (NGF) in the lung and the visceral sensory afferent system (C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord) of asthmatic guinea pigs.

Methods: Forty guinea pigs were divided to four groups, a saline control group (group A, n = 8), a provocation alone control group (group B, n = 8), an asthmatic group (group C, n = 12) and an anti-NGF group (group D, n = 12). The alterations of PKC immunoreactivity were investigated by means of immunohistochemistry in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of all groups. The expressions of NGF and PKC were investigated by Western blot in the lung, C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of all groups. The results were analyzed by the Luzex-F real time image analysis system and the gel imaging analysis system respectively.

Results: (1) Immunohistochemistry results: The absorbency (A) values of PKC were 0.102 +/- 0.009, 0.113 +/- 0.009, 0.106 +/- 0.005 and 0.116 +/- 0.007 in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group A and group B respectively. There was no significant difference between group A and group B (P > 0.05). The A values of PKC were 0.215 +/- 0.014 and 0.176 +/- 0.010 respectively in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group C, which were significantly different compared with group A (P < 0.01). The A values of PKC were 0.140 +/- 0.008 and 0.130 +/- 0.011 respectively in the C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group D, which were significantly different compared with group C (P < 0.01). (2) Western blot results: Compared with group A (the relative A values were 0.51 +/- 0.02, 0.43 +/- 0.01 and 0.92 +/- 0.02 respectively) and group B, the expression of PKC (the relative A values were 1.51 +/- 0.01, 1.40 +/- 0.03 and 2.22 +/- 0.02 respectively) increased markedly in the lung, C(7)-T(5) spinal ganglia and the corresponding posterior horn of the spinal cord of group C; however, the expression of PKC of group D (the relative A values were 0.80 +/- 0.03, 0.83 +/- 0.01 and 1.12 +/- 0.02 respectively) decreased markedly in comparison with group C.

Conclusion: The present results indicate that PKC might be involved in the pathogenesis of bronchial asthma, and NGF can upregulate the expression of PKC.