الفهرس 
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Abstract
The therapeutic efficacy of red palm oil in various disorders has been researched extensively. As a rich source of carotenes, RPO has been investigated as a fortification strategy to combat vitamin A deficiency in the developing world.
Vitamin A deficiency is a public health problem in more than half of all countries, especially in Africa and South-East Asia, it is also associated with increased rates of death from severe infections, especially in developing countries.
Vitamin A deficiency induces several general and oral manifestations. The development of periodontal disease by affecting the gingival epithelium is one of the most frequent and troublesome symptoms associated with vitamin A deficiency.
Aim of the study:
This study priority was to evaluate the effect of red palm oil against effects induced by vitamin A deficiency on gingival tissues of rats and to assess the effects of vitamin A deficiency on gingival tissue.
Materials and Methods:
Twenty-one adult male albino rats, two weeks old, were used in the present study. The animals were housed in separate cages in the Medical Research Centre, Faculty of Medicine, Ain Shams University, under controlled temperature and dark-light cycle. They were kept in wire mesh cages, seven rats per cage and were divided into:
• group I (Negative control group): Contains seven rats, each rat received normal diet for 60 days.
• group II (VAD group): Contains seven rats, each rat received white flour diet for 60 days.
• group III (RPO group): Contains seven rats, each rat received white flour diet for 60 days and then red palm oil–based baking fat (providing 2mg of red palm oil per kilogram of body weight per day) was incorporated into normal rat chow for 4 weeks.
Serum retinol level was assessed two times, after 2 months from the experiment and at the end of the experiment by HPLC (high-performance liquid chromatography).
At the end of the study period (88 days) all rats were sacrificed, and gingival tissue was excised and fixed immediately in 10% formalin solution for 48 hours, embedded in paraffin wax blocks and sectioned then mounted on glass slides.
1)Histological examination:
Sections were stained with Hematoxylin & Eosin for histological examination.
2) Histochemical examination:
Sections were stained with Masson Trichrome to detect collagen fiber synthesis.
3) Immunofluorescent examination:
The gingival specimens were examined for the expression of the Ki-67 antigen in the gingival tissues. The animals’ dead bodies remained were get rid off in the incinerator of Ain Shams Hospital.
4) Morphometric and Statistical analysis:
to estimate the keratin thickness and area percent of new collagen.
Results:
Histological examination of the gingival tissue of the rats of group II (VAD group) showed that the covering epithelium appeared with apparent hyperkeratosis with an apparent reduction in the size and prominence of rete pegs, and the basement membrane appeared less defined. While the lamina propria showed an obvious decrease in collagen bundles, thinning of wall of blood vessels with extravasated blood and areas of disintegration within the reticular layer of the lamina propria.
Histochemical examination of the gingival tissues of the rats of group II (VAD group) by Masson Trichrome staining group revealed a decreased new to old collagen ratio.
Histological examination of the gingival tissues of the rats of group III (RPO group) revealed a significant decrease in the keratin layer with a noticeable change in rete pegs to be similar to that of the control group. The lamina propria showed a noticeable augmentation in collagen bundles, an improvement in the extracellular matrix architecture and a notable reduction in areas of degeneration.
Histochemical examination of the gingival tissues of the rats of group III (RPO group) by Masson Trichrome staining group revealed an increase in the ratio of new to old collagen, indicative of enhanced collagen synthesis.
Immunofluorescence examination of the gingiva of group II (VAD group) revealed a positive nuclear ki-67 immuno-expression in the basal, suprabasal cells.
Immunofluorescence examination of the surface epithelium of the gingiva of group III (RPO group) revealed the basal and suprabasal layer with a slight decrease in the number of positively stained cells to Ki-67.
Statistical analysis regarding the keratin thickness showed the greatest mean diameter was recorded in VAD group, whereas the lowest value was recorded in control group. One way analysis of variance (ANOVA) test revealed that the difference between all groups was statistically significant (P<0.0001). Tukey’s post hoc revealed significant difference between each two groups.
Statistical analysis regarding area percent of new collagen showed the greatest mean area percent was recorded in RPO group, whereas the lowest value was recorded in control group. One way analysis of variance (ANOVA) test revealed that the difference between all groups was statistically significant (P<0.003). Tukey’s post hoc revealed no significant difference between control and RPO groups.