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Histopathology of melanosis coli and determination of its associated genes by comparative analysis of expression microarrays.

Li XΑ, Zhou Y, Zhou SΧ, Liu HR, Xu JM, Gao L, Yu XJ, Li XH - Mol Med Rep (2015)

Bottom Line: The results demonstrated that the pigment deposits in MC consisted of lipofuscin.Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue.The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli.

View Article: PubMed Central - PubMed

Affiliation: The Gastroenterology Tumor and Microenvironment Laboratory, Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China.

ABSTRACT
Melanosis coli (MC) refers to the condition characterized by abnormal brown or black pigmentation deposits on the colonic mucosa. However, the histopathological findings and genes associated with the pathogenesis of melanosis coli remain to be fully elucidated. The present study aimed to examine the histopathological features and differentially expressed genes of MC. This involved performing hematoxylin and eosin staining, specific staining and immunohistochemistry on tissues sections, which were isolated from patients diagnosed with MC. DNA expression microarray analysis, western blotting and immunofluorescence assays were performed to analyze the differentially expressed genes of melanosis coli. The results demonstrated that the pigment deposits in MC consisted of lipofuscin. A TUNEL assay revealed that a substantial number of apoptotic cells were present within the macrophages and superficial lamina propria of the colonic epithelium. Expression microarray analysis revealed that the significantly downregulated genes were CYP3A4, CYP3A7, UGT2B11 and UGT2B15 in melanosis coli. Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue. The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli. This novel information can be used to assist in further investigations of melanosis coli.

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Specific staining and immunohistochemistry for pigment detection in MC tissues. (A) Lipofuscin, periodic acid Schiff reaction demonstrated the presence of lipofuscin, which appears as purple particles. Bile, ferric chloride in trichloroacetic acid medium analysis revealed the absence of bile. Melanin, no obvious black particles were observed following Masson-Fontana ammoniacal silver staining. Hemosiderin, prussian blue staining for ferric ions revealed a negative result for hemosiderin in tissue. Magnification, x40. (B) Paraffin wax-embedded tissues stained using a melanin-antibody. No melanin expression was observed in the MC tissues. Magnification, x40. MC, melanosis coli.
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f2-mmr-12-04-5807: Specific staining and immunohistochemistry for pigment detection in MC tissues. (A) Lipofuscin, periodic acid Schiff reaction demonstrated the presence of lipofuscin, which appears as purple particles. Bile, ferric chloride in trichloroacetic acid medium analysis revealed the absence of bile. Melanin, no obvious black particles were observed following Masson-Fontana ammoniacal silver staining. Hemosiderin, prussian blue staining for ferric ions revealed a negative result for hemosiderin in tissue. Magnification, x40. (B) Paraffin wax-embedded tissues stained using a melanin-antibody. No melanin expression was observed in the MC tissues. Magnification, x40. MC, melanosis coli.

Mentions: Specific staining and immunohistochemical analyses of the MC tissues indicated that the pigment granules in the lamina propria indicated lipofuscin, but not melanin, bile pigment or hemosiderin. PAS is used to detect the presence of lipofuscin. Light microscopy of the stained sections revealed blue nuclei, a pale red gland cavity and several uniform purple particles in the lamina propria, and there were higher numbers of purple particles in the MC sections, compared with the normal sections. In addition, no green or blue staining was identified to indicate the presence of bile pigment and hemosiderin, and no obvious black particles were observed in the specimens (Fig. 2A). To confirm the type of pigmentation, 26 MC tissues and 10 normal colon tissues were analyzed using immunohistochemistry. The results indicated that the expression of melanin was absent in the MC and normal colon tissues (Fig. 2B). These results confirmed that the pigment deposits in MC were lipofuscin, not melanin.


Histopathology of melanosis coli and determination of its associated genes by comparative analysis of expression microarrays.

Li XΑ, Zhou Y, Zhou SΧ, Liu HR, Xu JM, Gao L, Yu XJ, Li XH - Mol Med Rep (2015)

Specific staining and immunohistochemistry for pigment detection in MC tissues. (A) Lipofuscin, periodic acid Schiff reaction demonstrated the presence of lipofuscin, which appears as purple particles. Bile, ferric chloride in trichloroacetic acid medium analysis revealed the absence of bile. Melanin, no obvious black particles were observed following Masson-Fontana ammoniacal silver staining. Hemosiderin, prussian blue staining for ferric ions revealed a negative result for hemosiderin in tissue. Magnification, x40. (B) Paraffin wax-embedded tissues stained using a melanin-antibody. No melanin expression was observed in the MC tissues. Magnification, x40. MC, melanosis coli.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581826&req=5

f2-mmr-12-04-5807: Specific staining and immunohistochemistry for pigment detection in MC tissues. (A) Lipofuscin, periodic acid Schiff reaction demonstrated the presence of lipofuscin, which appears as purple particles. Bile, ferric chloride in trichloroacetic acid medium analysis revealed the absence of bile. Melanin, no obvious black particles were observed following Masson-Fontana ammoniacal silver staining. Hemosiderin, prussian blue staining for ferric ions revealed a negative result for hemosiderin in tissue. Magnification, x40. (B) Paraffin wax-embedded tissues stained using a melanin-antibody. No melanin expression was observed in the MC tissues. Magnification, x40. MC, melanosis coli.
Mentions: Specific staining and immunohistochemical analyses of the MC tissues indicated that the pigment granules in the lamina propria indicated lipofuscin, but not melanin, bile pigment or hemosiderin. PAS is used to detect the presence of lipofuscin. Light microscopy of the stained sections revealed blue nuclei, a pale red gland cavity and several uniform purple particles in the lamina propria, and there were higher numbers of purple particles in the MC sections, compared with the normal sections. In addition, no green or blue staining was identified to indicate the presence of bile pigment and hemosiderin, and no obvious black particles were observed in the specimens (Fig. 2A). To confirm the type of pigmentation, 26 MC tissues and 10 normal colon tissues were analyzed using immunohistochemistry. The results indicated that the expression of melanin was absent in the MC and normal colon tissues (Fig. 2B). These results confirmed that the pigment deposits in MC were lipofuscin, not melanin.

Bottom Line: The results demonstrated that the pigment deposits in MC consisted of lipofuscin.Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue.The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli.

View Article: PubMed Central - PubMed

Affiliation: The Gastroenterology Tumor and Microenvironment Laboratory, Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China.

ABSTRACT
Melanosis coli (MC) refers to the condition characterized by abnormal brown or black pigmentation deposits on the colonic mucosa. However, the histopathological findings and genes associated with the pathogenesis of melanosis coli remain to be fully elucidated. The present study aimed to examine the histopathological features and differentially expressed genes of MC. This involved performing hematoxylin and eosin staining, specific staining and immunohistochemistry on tissues sections, which were isolated from patients diagnosed with MC. DNA expression microarray analysis, western blotting and immunofluorescence assays were performed to analyze the differentially expressed genes of melanosis coli. The results demonstrated that the pigment deposits in MC consisted of lipofuscin. A TUNEL assay revealed that a substantial number of apoptotic cells were present within the macrophages and superficial lamina propria of the colonic epithelium. Expression microarray analysis revealed that the significantly downregulated genes were CYP3A4, CYP3A7, UGT2B11 and UGT2B15 in melanosis coli. Western blotting and immunofluorescence assays indicated that the expression of CYP3A4 in the normal tissue was higher than in the MC tissue. The results of the present study provided a comprehensive description of the histopathological characteristics and pathogenesis of MC and for the first time, to the best of our knowledge, demonstrated that the cytochrome P450‑associated genes were significantly downregulated in melanosis coli. This novel information can be used to assist in further investigations of melanosis coli.

Show MeSH
Related in: MedlinePlus