RESUMO
<p><b>AIM</b>To investigate the role of the Chinese herbal medicine Xianhuayin on the reversal of 7,12-dimethylbenz[a]anthracene (DMBA)-induced premalignant mucosal lesions in the oral buccal pouch of golden hamsters.</p><p><b>METHODOLOGY</b>The animals were randomly divided into a non-diseased control group (n=5) and an experimental group including 50 animals in which the buccal mucosa had been painted with DMBA (0.5% in acetone) to generate an oral mucosa premalignant lesion. Animals in the experimental group were further divided into Xianhuayin-treated group (n=30), untreated premalignant lesion group (n=10) and normal saline (NS)-treated group (n=10). The cheek (buccal) pouch mucosa of the golden hamsters in each group was observed with light and electron microscopy eight weeks after intragastric administration with NS or Xianhuayin.</p><p><b>RESULTS</b>In the non-diseased control group, the buccal mucosa was keratinized and stratified squamous epithelium under a light microscope. In the untreated premalignant lesion group, variable degrees of epithelial dysplasia was observed. The irregular epithelial mucosa gradually became distinct in the Xianhuayin-treated group. Scanning electronic microscopic (SEM) analysis showed that surface of the cells exhibited honeycomb structures in the hamster of untreated-group. The cells were morphologically irregular, overlapped and loosened in the untreated premalignant lesion group. Most of the cell surface exhibited honeycomb structure in the Xianhuayin-treated group. Transmission electronic microscopic (TEM) analysis showed that buccal mucosal epithelial cells were morphologically regular in the non-diseased control group. Desmosomes and tonofibrils were reduced and the nucleus was morphologically irregular in the untreated premalignant lesion group. In the Xianhuayin-treated group, the widening intercellular gap was gradually reduced, desmosomes and the cells becoming morphologically regular. No significant difference was observed between the hamsters in NS-treated group and those in the untreated premalignant lesion group. Significant therapeutic efficacy was observed in the group receiving Xianhuayin.</p><p><b>CONCLUSION</b>Xianhuayin is effective in the reversal of DMBA-induced premalignant lesions in the buccal pouch of golden hamsters.</p>