[Experimental studies for botulinum toxin type A to antagonist the VIP/PACAP expression on nasal mucosa in allergic...

To explore the expression and significance of vasoactive intestinal peptide and Pituitary adenylate cyclase activiting polypeptide (VIP/PACAP) of nasal mucosa in rats with allergic rhinitis (AR), and the function of botulinum toxin-A(BTX-A) to inhibit the expression of VIP/PACAP in AR.

Thirty Sprague-Dawley rats were randomly divided into 3 groups, which were the AR group, the intervention group, and the control group. In the AR group, ovalbumin was used to sensitize healthy rats. In the intervention group, BTX-A was dripped into the nasal cavity of AR rats 7 times. In the control group, only physiological saline was used to drip into the nasal cavity of AR rats. Changes of the rats' behavior were observed. ELISA were used to detected the concentration variation of serum IFN-γ and IL-4. Histopathology and immunohistochemistry were employed to observe morphology in the rats' nasal mucosal and the expression of VIP/PACAP. Statistical analysis was also made.

(1)The typical symptoms marks of nasal scratching, sneezing, nasal blockage and rhinorrhea of AR group (7.5 ± 0.50) were higher than intervention group (1 ± 0.27) and control group (0.8 ± 0.31). (2) Comparing to intervention group and control group, the serm IFN-γ of the AR group obvious reduced (P < 0.05), the serm IL-4 of the AR group obvious rose (P < 0.01), and the serm Th1/Th2 (IFN-γ/IL-4) of the AR group obvious reduced (P < 0.01). (3) Comparing to intervention group and control group, the cilium loss, inflammatory cells infiltration, and inflammatory cells exudation of nasal mucosa in AR group were more obviously (P < 0.01), and the intervention group of the 3 indexes was obviously than control group. (4) The expression of VIP in the rats' nasal mucosa of the AR group (13.27 ± 2.74) were more intense than intervention group (5.21 ± 2.18) and control group (3.56 ± 5.30) (P < 0.01), and the expression of PACAP in the rats' nasal mucosa of the AR group (20.97 ± 2.14) were more intense than intervention group (6.33 ± 3.04) and control group (4.63 ± 1.25) (P < 0.01). (5) In all the 3 groups, there was positive correlation between expression of negative in VIP/PACAP and Thl/Th2 cell infiltration(r were respectively -0.340 and -0.223, P < 0.05).

The VIP/PACAP in the rats' nasal mucosa may play an important role in pathogenesis of AR, and BTX-A could improve the symptoms of AR through inhibition of the expression of VIP/ PACAP.