| Dry eye syndrome(DES) is a multi-factor common desease, which both abnormal tear filmand ocular surface can lead to. According to statistics, DES is regarded as one of the mostcommon deseases of ocular surface and undermines millions of people’s health all around theworld without effective treating method. Therefore, unveiling the pathogenesis and searchingnovel and effective methods become two of the most urgent issues in the area ofophthalmology.Herein, a rabbit model of surgery secondary DES was successfully established by removinglacrimal gland and harderian gland, nictitating membrane and then burning bulbar conjunctivawith trichloroacetic acid. Compared with the normal group, the results showed that theexperimental group had higher Schirmer value, along with nearly diminished fern-like crytalin tear, higher osmotic pressure, strongly postive result of living dyeing of ocular surface anddefects of cornea and conjunctiva. Moreover, the relationship among the former changes, themodel and the transformation of the ocular surface was discussed, a possible pathogenesiswas also proposed.Until now, pharmacotherapy is still the key treatment for DES, annual sales could reach tobillions of dollar for artificial tears all over the world. But there are some limitations fortraditional artificial tears, such as low effectiveness, strong drug dependency and can notmimic the function and structure of natural tear film. In our study, an artificial tear composedof Hyaluronic acid sodium/Chitosan(HA/CS) was evaluated and its effectiveness in vivo wasalso characterized. Fouty-eight New Zealand white rabbits were divided into six groupsrandomly: model group, negative control group, positive control group, low drugconcentration (0.1%HA/CS) group, medium drug concentration (0.25%HA/CS) group andhigh drug concentration (0.5%HA/CS) group. Two drops of the corresponding drugs weredropped into rabbits’ eyes and the dosing frequency was three times a day, the process of this treatment lasted28days. The results showed that each group of drugs can reduce the clinicalsymptom, that was relevant with the concentration of the as-prepared drug. The0.25%HA/CS solution was more effective in improving the objective signs of dry eye comparedwith the commercially available eyedrop. Researches showed that the amount of tearincreased, type I fern-like crystal as the main crystal phase produced, the status of highosmotic pressure of tear improved, and the rose benger staining for the treating eyes presentedweak positive, the result of fluorescent staining presented negative, the epithelial tissue ofocular surface was close to normal, the amount and quality of conjunctival goblet cells wasrecovered gradually. All of these results had proved the effectiveness of the as-prepared drug.The epithelium tissue of positive group recovered slightly, while the adsorption ofinflammation was not ideal, the type of the main crystal phases were III and IV type offern-like crystals, the osmotic pressure of tear was high, the morphology of the goblet cellswere abnormal. Moreover, its high drug dependence could be indicated from the repeatedsymptoms after drug discontinuance.Therapeutic effect of the HA/CS tear drops was characterized, and the curative mechanismwas also disscussed in detail, which includes the following processes, such as promotingscretion of tear and the formation and stability of the tear film, facilitating the healing processof pathological structure of abnormal ocular surface and the recovery of conjunctival gobletcells. It could also increase the scretion of mucoproteins and inhibit the cell apoptosis andinfiltration of the inflammatory cells at microenviroment of ocular surface. Therefore, theas-prepared drug, with a favorable application prospect, is a new choice for the clinicaltreatment of DES. |
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