Hyperosmolar saline is a proinflammatory stress on the mouse ocular surface
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Updated: Aug 15, 2026
Induction of Ocular Surface Inflammation and Collection of Involved Tissues
Published on: August 4, 2022
Lihui Luo1, De-Quan Li, Rosa M Corrales
1Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA.
Purpose:
To investigate whether hyperosmolar stress stimulates production of inflammatory mediators and activates the mitogen-activated protein kinase (MAPK) signaling pathways, c-jun n-terminal kinases (JNKs), extracellular-regulated kinases (ERKs), and p38 on the mouse ocular surface.
Methods:
129SvEv/CD-1 mixed mice were treated with a balanced salt solution (BSS) (305 mOsM) or a hyperosmotic saline solution (HOSS) (500 mOsM). Untreated age-matched mice were used as controls. The concentrations of interleukin 1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) were measured by enzyme-linked immunosorbent assay. Gelatinase activity was determined by in situ zymography. Corneal and conjunctival epithelia were lysed for Western blot with MAPK antibodies or used for semiquantitative reverse transcription and polymerase chain reaction and gene array.
Results:
Compared with age-matched controls and mice treated with BSS, the concentration of IL-1beta in tear fluid washings and the concentrations of IL-1beta and TNF-alpha and gelatinolytic activity in the corneal and conjunctival epithelia were significantly increased in mice treated with HOSS for 2 days. The expressions of IL-1beta, TNF-alpha, and matrix metalloproteinase 9 (MMP-9) messenger RNA by the corneal and conjunctival epithelia were also notably stimulated in mice treated with HOSS. The levels of phosphorylated JNK1/2, ERK1/2, and p38 MAPKs in the corneal and conjunctival epithelia were slightly increased in mice treated with BSS, but markedly increased in mice treated with HOSS.
Conclusions:
These results show that the hyperosmolarity stimulates expression and production of IL-1beta, TNF-alpha, and MMP-9 and activates JNK, ERK, and p38 MAPK signaling pathways on the mouse ocular surface. These findings suggest that hyperosmolar stress, as it may occur in dry eye, promotes ocular surface inflammation.
Insights
Hyperosmolar stress on the mouse ocular surface increases inflammatory mediators like IL-1beta and TNF-alpha. This stress also activates key signaling pathways (MAPK), suggesting a role in dry eye inflammation.
Area of Science:
- Ophthalmology
- Molecular Biology
- Immunology
Background:
- Dry eye disease is a prevalent condition often associated with ocular surface inflammation.
- Hyperosmolarity of the tear film is a significant factor contributing to dry eye symptoms and pathology.
- Understanding the molecular mechanisms underlying hyperosmolarity-induced inflammation is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the effect of hyperosmolar stress on the production of inflammatory mediators on the mouse ocular surface.
- To determine if hyperosmolar stress activates mitogen-activated protein kinase (MAPK) signaling pathways, including JNK, ERK, and p38.
- To elucidate the role of these molecular events in the context of ocular surface inflammation.
Main Methods:
- Mice were exposed to hyperosmotic saline solution (HOSS) or balanced salt solution (BSS) for 2 days.
- Tear fluid and ocular surface tissues (corneal and conjunctival epithelia) were collected for analysis.
- Levels of inflammatory mediators (IL-1beta, TNF-alpha), gelatinase activity, and MAPK activation were measured using ELISA, zymography, Western blot, and RT-PCR.
Main Results:
- HOSS significantly increased IL-1beta and TNF-alpha concentrations in tear fluid and ocular tissues compared to controls.
- Gelatinolytic activity and the expression of IL-1beta, TNF-alpha, and MMP-9 mRNA were notably elevated in HOSS-treated mice.
- Activation of JNK, ERK, and p38 MAPK signaling pathways was markedly increased in the ocular surface epithelia of HOSS-treated mice.
Conclusions:
- Hyperosmolar stress stimulates the production of key inflammatory mediators (IL-1beta, TNF-alpha) and MMP-9 on the mouse ocular surface.
- Hyperosmolarity activates the JNK, ERK, and p38 MAPK signaling pathways in ocular surface tissues.
- These findings support the hypothesis that hyperosmolar stress contributes to ocular surface inflammation, as observed in dry eye conditions.
