A bio-mathematical model of time prediction in corneal angiogenesis after alkali burn
Introduction
In the process of wound healing, the vascularization of cornea plays a pivotal role with its effect of double-edged sword that impacts the clinical treatment of deep corneal trauma especially in alkali burn directly. Thus, the determination of angiogenesis time is the key prerequisite to obtaining a balance between valid repair and excess angiogenesis and to different treatments before and after corneal angiogenesis.
However, the angiogenesis time of cornea is difficult to be determined by common research after trauma, for it is regulated by many factors such as injury degree, individual difference, interaction of cytokines in vivo, influence of different signal transduction pathway in vivo, surrounding irritation, repairing environment and so on [1], [2], [3]. Accordingly, it is the result of interaction between promotion and inhibition factors in vivo and the expression of single typical factor showed the effect of many factors with similar role.
As one type of artificial neural network (ANN), back propagation neural network (BP neural network) is suitable to solve this difficulty for it owned obvious superiority under some conditions as follows: the problem is not solved well by common methods, especially the problem is not known and can hardly be expressed exactly [4], [5]. Thus, the investigation adopts certain parameters as input and output vectors which reflect the typical process of corneal angiogenesis such as vegf and tsp2 in order to establish a bio-mathematical model to predict the angiogenesis time after alkali burn by BP neural network [6], [7], [8].
Section snippets
Experimental animals
Twenty-four pregnant mice were purchased from Medical Laboratory Animal Center of Institute of Surgery Research, Daping Hospital, Third Military Medical University. After spontaneous delivery, the baby mice were divided into 24 groups according to every nest with randomized female and male. Ten days after ablactating, they were used in the experiment. The investigation was approved by the research council and animal use and care committee of Daping Hospital, Third Military Medical University.
Alkali burn treatment
Corneal morphological changes and angiogenesis
Alkaline is double intermiscibility (water solubility and liposolubility) so it passes epithelium barrier easily and enters into the cells to destroy the inner cellular structure quickly and make it necrose. After treated by 0.01 mol/l NaOH, the corneas of mice mainly showed the following symptoms: epithelial lamina shrank, some tissues dissolved and alkaline substance lasted to infiltrate to the deep lamella of tissue. Meanwhile, vascular endothelial cells moved and differentiated rapidly.
Discussion
As a tissue with transparency and avascularity, cornea locates in the outside of the eyeball and will bear many kinds of injuries from ocular trauma. Some negligible injuries to other tissues may cause serious corneal consequence, especially in corneal chemical burn. The vascularization of cornea will occur when the wound depth exceeded the epithelial lamina, such as to the limbus or to the Bowman's lamina [9], [10].
Corneal angiogenesis is the result of coordination of many factors which
Acknowledgments
The work was supported by the National Key Basic Research and Development Plan of China (973 Project, 2005CB522602) and Postdoctoral Science Foundation of China (2005037165) and Natural Scientific Foundation of Chongqing (CTSC, 2004BB5251).
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