[A primary study of L-carnitine protective effect on corneal and conjunctival epithelium of mouse dry eye model induced by hyperosmolar saline].
OBJECTIVE
To evaluate protective effects of L-carnitine on corneal and conjunctival epithelium of mouse dry eye model induced by hyperosmolar saline.


METHODS
Sixty female BALB/c mice at the age of 6 - 8 weeks were randomly divided into three groups (20 in each): Hyperosmolar saline group (HO), Hyperosmolar and Isosmotic saline group (HO + IO), as well as Hyperosmolar saline and 1% L-carnitine group (HO + 1%LCA). The HO group was treated with 500 mOsmol/L sodium chloride solution; the HO + IO group with 308 mOsmol/L sodium chloride solution first and 500 mOsmol/L sodium chloride solution 30 minutes later; and the HO + 1%LCA group with 1%L-carnitine eye drop first and 500 mOsmol/L sodium chloride solution 30 minutes later. Alternately, 5 times a day for 28 days. Corneal fluorescein staining, corneal epithelial hematoxylin-eosin staining and thickness measurement, conjunctival epithelial periodic acid-schiff reagent staining and goblet cell counting were conducted on 0, 7th, 14th and 28th days, respectively. On 28th day, corneal surface was inspected by scaning electron microscopy and tear osmolarity was measured.


RESULTS
In HO or HO + IO group, compared with HO + 1%LCA group, the number of goblet cells was reduced, the score of corneal fluorescein staining and corneal epithelial thickness was elevated: on 7th day, there was difference noticed in the corneal epithelial thickness [(27.7 ± 1.1), (26.5 ± 1.4), (25.1 ± 1.0) µm, P < 0.01] and the number of goblet cell [(11.9 ± 1.1), (12.1 ± 0.9), (13.3 ± 0.9), P < 0.01] in 3 groups; on 14th day, there was evident change in the corneal fluorescein staining area [(3.2 ± 0.9), (2.9 ± 0.7), (1.7 ± 0.8), χ(2) = 11.465, P < 0.01] in 3 groups. On 28th day, Increased tear osmolarity and lowered microvilli on cornea were examined in HO [(327.37 ± 4.20) mOsmol/L] or HO + IO [(324.36 ± 5.72) mOsmol/L] group compared with HO + 1%LCA [(308.29 ± 5.72) mOsmol/L] group (P < 0.01).


CONCLUSIONS
L-carnitine had protective effect on corneal and conjunctival epithelium of mouse dry eye model induced by hyperosmolar saline, and should be studied further.
Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China.
Jian
J
Huo
Han-ping
HP
Xie
Jing
J
Li
Dan
D
Zhou
D000818:Animals; D002331:Carnitine / Q000494:pharmacology*; D003228:Conjunctiva / Q000166:cytology / Q000187:drug effects; D003315:Cornea / Q000166:cytology / Q000187:drug effects; D004195:Disease Models, Animal; D004848:Epithelium / Q000187:drug effects*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D012462:Saline Solution, Hypertonic / Q000009:adverse effects; D014985:Xerophthalmia / Q000139:chemically induced / Q000188:drug therapy*
D012462:Saline Solution, Hypertonic; D002331:Carnitine