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A study of cellular responses to retinal laser photocoagulation in the miniature pig
Başlık:
A study of cellular responses to retinal laser photocoagulation in the miniature pig
Yazar:
Xiao, Ming, author.
ISBN:
9780438043886
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (334 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Özet:
The established primary therapy for the vasoproliferative retinopathies is panretinal photocoagulation which results in the regression of preretinal new vessels. Despite the success of laser therapy, its mode of action at the cellular level remains unclear, but may be associated with a change in growth factor profiles within the retina. Hence the aim of this thesis was to study the cellular responses and growth factor profiles at different times following panretinal photocoagulation. Eighteen adult miniature pigs were divided into two groups which received scatter photocoagulation by either diode or Emerald laser. Ocular samples (vitreous and retina) were isolated at different times (up to 42 days) post-laser and analysed using a variety of techniques, i.e. histology, immunohistochemistry, ELISA, radioimmunoassay and Western ligand blotting, to identify 1) the cell types involved in the local retinal repair process, 2) areas of cell proliferation, 3) the expression of growth factors and their receptors in the area of the retinal lesion, and 4) the levels of growth factors in the vitreous. Non-lasered eyes were used as controls. Diode burns were extremely variable; some were light which were confined to the outer retina while others extended into the inner retina. The Emerald lesions were generally uniform and involved the inner retina. The histopathological appearance of these two laser lesions was identical during the retinal healing process, with RPE regeneration and glial scar formation in the burn area by 21 days post-laser. Retinal Muller cells, RPE cells, and retinal vascular endothelial cells were intimately involved in the retinal healing process. The proliferation of these cells was detected in burn areas from 4 days post-laser, with maximum proliferation observed at 4 days post-laser, regardless of laser type used. While immunostaining for all the growth factors (and the EGF-R) studied was evident in the unlasered retina, changes in expression were observed in the burn areas. Such changes were confined to the RPE and the outer nuclear layer (ONL), regardless of laser type used. The immunoreactivity within RPE cells of burn areas was either absent or decreased following laser treatment but returned to normal by 21 days. The immunoreactivity was increased within the ONL of burn areas during the healing process but returned to normal by 42 days. Vitreous TGF-152 levels were significantly decreased at 1 hour post diode laser and 4 and 7 days post Emerald laser, but returned to normal by 21 and 42 days respectively. Vitreous IGF-I levels were increased at 4 and 7 days post diode and Emerald laser respectively but all returned to normal by 21 days. IGFBP-2 levels followed a similar trend to those observed for IGF-I. No changes in vitreous levels of either bFGF, EGF, or insulin were observed following laser treatment. These studies have 1) confirmed the miniature pig as a good model for retinal photocoagulation studies, 2) identified the cellular nature of the wound healing responses, 3) demonstrated the temporal changes in growth factor expression in the retina following laser photocoagulation, and 4) highlighted significant changes in intravitreal growth factor levels following laser photocoagulation.
Notlar:
School code: 1543
Konu Başlığı:
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684325.1) | 684325-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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