Abstract: Pranoprofen & dry eye (mouse study)

Pranoprofen = an NSAID (non-steroidal anti-inflammatory). They're comparing sodium hyaluronate drops vs. SH plus this NSAID vs. SH plus FML (corticosteroid).

I sometimes find it interesting (sad too but won't dwell on that right now) what they use to cause corneal disease or dry eye in animal dry eye studies. They used to use PRK to induce limbal stem cell deficiency... now BAK (BAC, benzalkonium chloride) to induce dry eye. Of course this BAK percentage is exponentially higher than what they'd ever put in an eyedrop as a preservative but still, it tells you something when the most common eyedrop preservative is used to cause dry eye for study purposes.

[Therapeutic effects of Pranoprofen on the mouse dry eye induced by topical medication of Benzalkonium Chloride].

OBJECTIVE:
Randomized controlled experimental study to investigate the therapeutic effect and the possible mechanism of Pranoprofen on the recovery of dry eye induced by topical medication of Benzalkonium Chloride (BAC) in mouse.

METHODS:
It was an experimental study. Seventy BALB/c mice were treated with topical administration of 0.25% BAC to establish the dry eye condition. Based on the consistency of break-up time of tear-film (BUT), corneal fluorescein staining scores and inflammation index, the eyes were re-selected and randomly divided into four groups on day (D) 21 after the BAC treatment. Group A was set up as blank control, while group B, C and D were treated respectively with 0.1% sodium hyaluronate eye drops, 0.1% fluorometholone eye drops plus 0.1% sodium hyaluronate eye drops, 0.1% pranoprofen eye drops plus 0.1% sodium hyaluronate eye drops. BUTs, tear volumes, corneal fluorescein staining scores and inflammation index were evaluated in each group on D0, 1, 3 and 5 after the therapeutic treatment. Global specimens were collected on D6. Sections were stained with hematoxylin and eosin (HE) or by periodic acid-schiff (PAS) assay, and labeled with cytokeratin 10 (K10) antibody. The expression of tumor necrosis factor-α (TNF-α) in the cornea and conjunctiva was quantified by western blot.

RESULTS:
72 eyes were included in the sequential experiment, 18 eyes for each group. On D0, 1 and 3, no clinical differences were observed among the groups. On D5, the BUT was (2.933 ± 0.320), (2.900 ± 0.280), (3.464 ± 0.498) and (3.643 ± 0.413) s in group A, B, C and D respectively; the BUTs in group C and D were significant longer than those of group A and B (F = 13.774, P = 0.000). The corneal fluorescein staining score was (11.640 ± 1.008), (11.790 ± 1.188), (10.330 ± 1.371) and (10.270 ± 1.104)s in group A, B, C and D respectively; the scores in group C and D were significant lower than those of group A and B (F = 6.145, P = 0.001). The corneal inflammatory index was (0.232 ± 0.059), (0.229 ± 0.078), (0.151 ± 0.055) and (0.154 ± 0.056) in group A, B, C and D respectively; the index in group C and D were significant lower than those of group A and B (F = 6.703, P = 0.001). No significant difference was found in tear volume among groups. No significant difference was found between Pranoprofen and Fluorometholone treatment in BUT, corneal fluorescein score or inflammatory index. Corneal morphology showed the feature of thicker corneal epithelial layer in group A and uniformity in group C and D. PAS assay revealed similar goblet cell numbers in group C and D, but less goblet cells in group A and B. Cytokeratin 10 was almost negatively expressed in Pranoprofen or Fluorometholone treated groups, and remained positive in the corneal epithelium with other treatments. The level of TNF-αin the cornea was down-regulated in Pranoprofen or Fluorometholone treated groups.

CONCLUSIONS:
Pranoprofen or Fluorometholone combined with sodium hyaluronate treatment presented similar therapeutic effects on BAC-induced mouse dry eye, with the more stable tear film, the better regularity of epithelium recovery, the down-regulation of inflammatory TNF-α, the increased number of goblet cells, and the elimination of squamous metaplasia, when compared with the treatment of sodium hyaluronate eye drops only. Our results showed the great potentialities of Pranoprofen in the clinical treatment of ocular surface inflammation in the mild and severity dry eye.
[Article in Chinese]

He H, Liu ZG, Lin ZR, Liu XC, He H, Xiao QG.
Zhonghua Yan Ke Za Zhi. 2012 Jan;48(1):33-40.
Eye Institute and Affiliated Xiamen Eye Center of Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen 361005, China; Department of Ophthalmology, the Second Affiliated Hospital of Nanhua University, Hengyang 421001, China.