Inhibition of 4-NQO-induced F433 rat tongue carcinogenesis by oleuropein-rich extract.

Olive leaf extract provides nutritional support for detoxification at the cellular level, when the body is under stress. The present study aimed to evaluate the chemopreventive effect of oleuropein-rich extract (ORE) on 4-NQO-induced rat tongue carcinogenesis. Eighty male F344 rats, 6 weeks age were divided into 5 groups (10 animals each for groups 1 and 2 and 20 each for groups 3, 4, and 5). Group 1 served as an untreated control. Group 2 was given ORE-containing diet alone. Rats of groups 3, 4, and 5 were given daily 20 ppm 4-NQO in drinking water for 8 weeks. Group 4 was fed diets containing ORE, concomitantly with the time of carcinogen exposure and continued 1 week after its stoppage. Group 5 was fed diets mixed with ORE starting 1 week after cessation of 4-NQO treatment. The experiment was terminated when the rats aged 37 weeks, and all animals were euthanized. The tongues were carefully inspected for pathological lesions, excised, and were processed for c-Met and Ki-67 immunohistochemical examination. The gross inspection, histopathological and immunohistochemical results of the present study showed a beneficial regression effect of ORE on tumor progression, especially when it was administered concomitantly with 4-NQO rather than when given after the stoppage of the carcinogenic material. In conclusion, ORE has a chemopreventive role in tongue squamous cell carcinoma, and further studies are needed to explore the molecular mechanisms of its tumor suppressive effect at this level.

Long-term effect of Spirulina platensis extract on DMBA-induced hamster buccal pouch carcinogenesis (immunohistochemical study).

In cancer research, the use of complementary and alternative medicine has increased over the past decade. In this study, 80 male golden Syrian hamsters were divided into four equal groups; the right buccal pouches of the hamster rats in group 1 were painted with 0.5% solution of 7, 12-dimethylbenz[a]anthracene (DMBA), three times a week for 32 weeks. The same pouches of group 2 were subjected to the same DMBA painting; but at the same time, the animals received 10 mg/daily Spirulina platensis extract for the same period. In group 3, the same regimen of DMBA painting was done but for 24 weeks only and the daily systemically S. platensis was received for the 32 weeks. In group 4, neither DMBA painting nor S. platensis administration was done but pouches were painted with saline and served as a control one. Five rats from each group were sacrificed at 12, 24, 28, and 32 weeks, respectively. The required pouches were excised, fixed, and embedded in paraffin to be immunostained with proliferating cell nuclear antigen (PCNA). The results showed that increased PCNA expression was directly related to the severity of pathological alterations from normal epithelium to dysplasia and from dysplasia to squamous cell carcinoma (SCC) in the study groups at the different extended periods of DMBA application and S. platensis extract administration. Analysis of variance and Duncan's multiple-range test for PCNA labeling index were proved a high significant difference (P < 0.01) between the different groups. From the previous results, it can be concluded that S. platensis extract has a beneficial role in regression of cancer progression.

Effects of Spirulina platensis extract on Syrian hamster cheek pouch mucosa painted with 7,12-dimethylbenz[a]anthracene.

Research into cancer prevention seeks to identify the preventable causes of cancer, and to reduce cancer incidence by effective implementation of preventative strategies in target populations. In this study, 30 male golden Syrian hamsters were divided into three equal groups; the right buccal pouches of the hamster rats in group one were painted with 0.5% solution of 7,12-dimethylbenz[a]anthracene (DMBA), three times a week, until sacrificed. The same pouches of group two were also painted with DMBA, but received an additional 10mg/daily Spirulina platensis extract, which was added to the soft diet supplements during the same period. The hamster rats in group three received neither DMBA nor S. platensis extract. They were painted with saline and served as control animals. Half the hamsters from each of the three groups were sacrificed by ether inhalation after 7 weeks, and the remaining half were sacrificed after 14 weeks. The required buccal pouches were surgically excised and prepared for regular H&E and argyrophilic proteins of the nuclear organizer regions (AgNOR) silver staining. AgNORs counting and statistical analysis were carried out. We observed moderate dysplastic changes extending into the midspinous layer in group one 7 weeks after DMBA painting, which reached to half the thickness of the hyperplastic epithelium after 14 weeks. However, in group two, mild dysplastic changes were observed after 7 weeks, which were restricted to the basilar and parabasilar layers of the epithelium after 14 weeks of treatment. AgNOR staining in group one produced AgNOR counts ranging from one to seven dots per nucleus, whereas the counts were one or two dots per nucleus in group two. The AgNOR mean number in groups one, two and three was (3.1+/-0.006, 1.3+/-0.003 and 1.2+/-0.003, respectively). Moreover, with one sample t-test, a significant difference was found in AgNOR mean number between groups one and two, groups one and three and between groups two and three (P<0.05). An overall significant difference among the three groups (P<0.01) was indicated with one-way analysis of variance. The pAgNOR was 10% in group one, 5% in group two and 4% in group three. Consequently, S. platensis is an adjunctive means to inhibit the dysplastic changes occurring in the hamster cheek pouch (HCP) mucosa. However, more research is needed to expand its beneficial action.