Discussion
The process of nasal epithelization after ESS is closely related to the
recovery of symptoms. A previous study19 showed that
nasal irrigation with saline containing sodium hyaluronate improves
postoperative nasal symptoms and accelerated the process of nasal
epithelization. However, the evaluation indexes were subjective symptom
score and endoscopic score in patients 6 weeks after the operation, with
no direct evaluation of ciliary function recovery. In our study, we used
subjective symptom score and endoscopic score in patients as the primary
statistical index. We also collected the nasal mucosa of patients for
SEM analysis as a direct index of mucosal epithelization and ciliary
recovery. Our results showed the reduction of VAS, obstruction and
rhinorrhea scores for general symptom in rh-bFGF nasal experimental
group were significantly greater than in the control group, and SNOT-22
score reduction was significantly greater in the rh-bFGF nasal-drop
group compared to the control group 2 weeks after ESS, indicating that
intranasal use of rh-bFGF exerts obvious effects on rapid recovery of
symptoms in ESS postoperative patients. What’s more, a significant
reduction was found in in rh-bFGF experimental groups at 6 months and 1
year which indicated that rh-bFGF may exert an persistent effect on its
recovery. We performed a one-year recurrence and efficacy evaluation,
considering that epithelial damage of the nasal cavity is an important
factor causing the onset of sinusitis, we can predict that promoting
epithelialization and ciliary growth during the early stage is helpful
for reducing recurrence and polyp regeneration.
Th2-type CRS was associated with eosinophils and asthma.
Studies11,12 have shown that eosinophilic-associated
CRS presents more severe postoperative mucosal edema and polypoid
changes than non-eosinophilic CRS. In our study, one year follow-up data
for the eosinophilic CRS patients showed that the reduction in VAS
scores in the rh-bFGF nasal-drop group was greater than in the control
group. Moreover, the reduction in the L-K score in the rh-bFGF
nasal-spray group was greater than that in the control group. This
suggests that rh-bFGF may also contribute to the rapid recovery of
eosinophilic sinusitis patients. However, this trend was not obvious in
rh-bFGF experimental groups of non-eosinophilic patients compared with
control group. We analyzed the reason for this difference between
eosinophilic and non-eosinophilic CRSwNP, which was attributed to the
poorer ciliary coverage and sever epithelial damage in eosinophilic
CRSwNP. Therefore, we consider that rh-bFGF may improve the prognosis of
patients with CRSwNP by promoting ciliary growth and epithelial repair.
To further verify the mechanism of rh-bFGF on the rapid recovery of ESS
patients, epithelial cells of the experimental and the control groups
were examined by SEM. 2 weeks and 1 month after ESS, rh-bFGF nasal-spray
and rh-bFGF nasal-drop group exhibited a higher ciliary coverage
compared with control group. CP110, Foxj1 and Tap73 have already been
proven as ciliogenesis-associated makers20. The
expression of these three genes has been marked decreased in rh-bFGF
experimental groups compared with control group at 2 weeks and 1 month
after ESS, which was consistent with the result of SEM. These results
suggest that the outstanding improvement of postoperative nasal
obstruction, rhinorrhea, as well as the endoscope L-K score, were also
associated with rapid epithelialization and ciliary coverage.
The method of nasal administration is another highlight of our research
design. Previous studies21,22 have shown that changing
the administration method of local nasal corticosteroids may affect the
symptoms. Therefore, we designed a nasal-drop experiment group. The
reduction in the VAS score for general symptoms in the rh-bFGF
experimental groups was significantly greater than in the control group.
In terms of epithelialization and ciliary growth post-operation, the
rh-bFGF experimental groups may have the same effect on ethmoid mucosa
cilia growth, whereas mucosa from patients in the control group had
significantly less ciliated coverage. Therefore, the overall effect of
the nasal-drop group was better than that of the nasal-spray group. This
may be attributed to position drainage, which enables rh-bFGF to reach
the mucous of the ethmoid roof and frontal recess.