Type VII and XVII Collagen mRNA Expressions in Regenerated Epidermal Laminae in Chronic Equine Laminitis

To confirm ability forming the basement membrane of the regenerated laminar epidermis(rLE) in chronic laminitis, expression of type VII and type XVII collagen mRNAs in the rLEwas studied applying sequences of two type of murine collagens. On northern blot analysis,complement DNA (cDNA) probes adjusted from the murine type VII and type XVII collagencould hybridize with the equine mRNAs, and each signal was detected as single-bands atapproximately 9.5 kb and 5.6 kb, respectively. Contrasting with the expression level ofequine glyceraldehyde-3-phosphate dehydrogenease mRNA, the band of type VII collagen mRNAin laminitis was stronger than normal, but the type XVII collagen mRNA in laminitis wasless than normal. By in situ hybridization, positive signals in response to the murinetype VII and type XVII collagen mRNA probes could be detected in the equine laminitic rLEregion. From these results, it is concluded that the keratinocytes constructing the rLE inchronic stage of laminitis can express type VII and type XVII collagen mRNAs and theseexpression patterns were different from the normal.