Study The Effect Of Chitosan On NOS-II In The Model Of Corneal Alkali Burn

Objective To study the expression of NOS-II in corneas after alkali burn injury in rabbits and the effect of chitosan on NOS-II.Methods 21 New Zealand white rabbits were employed in the study. 18 rabbits(36eyes) corneal alkali burn models were reproduced. We set the right eyes as chitosan experimental group(n=18) and the left eyes as model control group( n = 18). the last 3 rabbits(6 eyes) as normal control group(n=6).the chitosan experimental group was treated with 2% chitosan four times a day, and the modes control and normal control groups with PBS four times a day. Six injured rabbits were sacrificed randomly at the 4th, 7th, and 14th day after injure. The rabbits of normal control group were sacrificed before the experiment termination. HE staining, immunocytochemistry (ICC) were employed to observe the expression of NOS-II in the corneal tissue of rabbits in all three groups animals above mentioned.Result The normal rabbit corneas expressed slightly NOS-II in the basis epithelium and stroma. The expression increased notedly in model control and chitosan experimental group(p<0.05). NOS-II can be expressed mainly in inflammation cells of stroma, corneal epithelium and the newly vessel endothelial cell. The strongest expression of NOS-II is at the 7th day. According to the statistics analysis, the expression of NOS-II at chitosan experimental group was more slight (p<0.05) than the model control group, and the inflammatory reaction was milder.Conclusion The expression of NOS-II in corneas after alkali burn injury in rabbits is remarkable and chitosan has a strong effect on inhibiting the expression of NOS-II and decreasing inflammatory reaction.Part II Study the effect of chitosan on MMPs and observe the therapeutic effect on the complication of corneas after alkali burn injury AbstractObjective To study the effect of chitosan on MMP-1,MMP-2 in corneas after alkali burn injury in rabbits and observe the therapeutic effect of chitosan on the corneal ulcer and neovascularization.Methods 27 New Zealand white rabbits were employed in the study. 24 rabbits(48eyes) corneal alkali burn models were reproduced. We set the right eyes as chitosan experimental group(n=18) and the left eyes as model control group( n = 18). the last 3 rabbits(6 eyes) as normal control group(n=6).the chitosan experimental group was treated with 2% chitosan four times a day, and the modes control and normal control groups with PBS four times a day. Digital slit lamp image system was used to observe the corneal ulcer and newly formed vessels. Six injured rabbits were sacrificed randomly at the 4th,7th, 14th and 21th day after injure. The rabbits of normal control group were sacrificed before the experiment termination. HE staining, immunocytochemistry (ICC) were employed to observe the expression of MMP-1,MMP-2 in the corneal tissue of rabbits in all three groups animals above mentioned. Result The normal rabbit corneas expressed slightly MMP-2 in the basis epithelium and stroma and nearly expressed no MMP-1. The expression increased notedly in model control and chitosan experimental group(p<0.05). MMPs can be expressed mainly in inflammation cells of stroma, corneal epithelium and the newly vessel endothelial cell. According to the statistics analysis, the expression of MMPs at chitosan experimental group was more slight (p<0.05) than the model control group, and the inflammatory reaction was milder. The corneal ulcer and CoNV were improved effectively.Conclusion Chitosan has strong effect on inhibiting the expression of MMPs and decreasing inflammatory reaction. Chitosan is effective on the corneal ulcer and CoNV after alkali burn injury.