Intranasal administration of recombinant human BDNF as a potential therapy for some primary headaches

Abstract

Background: In addition to its critical role in neurogenesis, brain-derived neurotrophic factor (BDNF) modulates pain and depressive behaviors.

Methods: In a translational perspective, we tested the anti-migraine activity of highly purified and characterized recombinant human BDNF (rhBDNF) in an animal model of cephalic pain based on the chronic and intermittent NTG administration (five total injections over nine days), used to mimic recurrence of attacks over a given period. To achieve this, we assessed the effects of two doses of rhBDNF (40 and 80 µg/kg) administered intranasally to adult male Sprague-Dawley rats, on trigeminal hyperalgesia (by orofacial formalin test), gene expression (by rt-PCR) of neuropeptides and inflammatory cytokines in specific areas of the brain related to migraine pain. Serum levels of CGRP, PACAP, and VIP (by ELISA) were also evaluated. The effects of rhBDNF were compared with those of sumatriptan (5 mg/kg i.p), administered 1 h before the last NTG administration.

Results: Both doses of rhBDNF significantly reduced NTG-induced nocifensive behavior in Phase II of the orofacial formalin test. The anti-hyperalgesic effect of intranasal high-dose rhBDNF administration in the NTG-treated animals was associated with a significant modulation of mRNA levels of neuropeptides (CGRP, PACAP, VIP) and cytokines (IL-1beta, IL-10) in the trigeminal ganglion, medulla-pons, and hypothalamic area. Of note, the effects of rhBNDF treatment were comparable to those induced by the administration of sumatriptan. rhBDNF administration at both doses significantly reduced serum levels of PACAP, while the higher dose also significantly reduced serum levels of VIP.

Conclusions: The findings suggest that intranasal rhBDNF has the potential to be a safe, non-invasive and effective therapeutic approach for the treatment of primary headache, particularly migraine.

Keywords: BDNF; Cluster headache; Intranasal administration; Migraine; Neuroinflammation; Neurotrophins.

Fig. 1

Experimental timeline for treatment and testing procedures. (A) NTG or its vehicle were administered i.p. every other day over nine days (five total injections). rhBDNF or its vehicle were administered intranasally every other day, alternating with NTG (four total injections). On the last day (day nine), 2 h after the last administration of NTG or vehicle the animals were subjected to the orofacial formalin test (45 min duration). Subsequently rats were sacrificed for samples collection. (B) In another experimental group rats were chronically treated with NTG (as reported above) and 1 h after the last administration (on day nine) they were injected with sumatriptan. One hour later they were subjected to behavioral test followed by sacrifice and samples collection as reported above

Fig. 2

Orofacial formalin test. Face rubbing time (in seconds) during Phase I (upper panel) and Phase II (lower panel) of the test. Data were tested for normality using the Shapiro-Wilk test and considered normal. We then applied the one-way ANOVA followed by post hoc Tukey’s multiple comparison test. Data are expressed as mean ± SD; * P < 0.05 and ** P < 0.01 vs. CT; ° P < 0.05, °° P < 0.01 and °°° P < 0.001 vs. NTG; ^^^ P < 0.001 vs. rhBDNF40; # P < 0.05 vs. rhBDNF80. n = 6–9

Fig. 3

Gene expression of CGRP (A), VIP (B), PACAP (C), IL-1beta (D) and IL-10 (E) in the trigeminal ganglion. Data were normally distributed following Shapiro-Wilk test, thus we applied the one-way ANOVA followed by post hoc Tukey’s multiple comparison test. Data are expressed as mean ± SD; ° P < 0.05, °° P < 0.01 and °°° P < 0.001 and vs. NTG. n = 6–9

Fig. 4

Gene expression of CGRP (A), VIP (B), PACAP (C), IL-1beta (D) and IL-10 (E) in the medulla-pons area. Data in A, C, D were normally distributed following Shapiro-Wilk test, thus we applied the one-way ANOVA followed by post hoc Tukey’s multiple comparison test. Data in B, E were not normally distributed following Shapiro-Wilk test, thus we applied the Kruskal–Wallis’s test followed by Dunn’s post-hoc test. Data are expressed as mean ± SD; °° P < 0.01 and °°° P < 0.001 vs. NTG; + P < 0.05 vs. NTG + rhBDNF80. n = 6–9

Fig. 5

Gene expression of CGRP (A), VIP (B),PACAP ( C), IL-1beta ( D) and IL-10 (E) in the hypothalamic area. Data in B, C, D were normally distributed following Shapiro-Wilk test, thus we applied the one-way ANOVA followed by post hoc Tukey’s multiple comparison test. Data in A, E were not normally distributed following Shapiro-Wilk test, thus we applied the Kruskal–Wallis’s test followed by Dunn’s post-hoc test. Data are expressed as mean ± SD; ° P < 0.05 and °°° P < 0.001 vs. NTG. n = 6–9

Fig. 6

Serum levels of CGRP (A-C), PACAP (D-F) and VIP (G-I). Data in D, E, F were normally distributed following Shapiro-Wilk test, thus we applied the one-way ANOVA followed by post hoc Tukey’s multiple comparison test. Data in A, B, C, G, H, I were not normally distributed following Shapiro-Wilk test, thus we applied the Kruskal–Wallis’s test followed by Dunn’s post-hoc test. Data are expressed as mean ± SD; * P < 0.05, ** P < 0.01 and *** P < 0.001 vs. CT; ° P < 0.05, °° P < 0.01 and °°° P < 0.001 vs. NTG; ^ P < 0.05, ^^ P < 0.01 and ^^^ P < 0.001 vs. rhBDNF40; # P < 0.05, ## P < 0.01 and ### P < 0.001 vs. rhBDNF80. n = 7–9