الفهرس 
INTRODUCTION AND REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
DM is a chronic metabolic disorder with high blood glucose levels. Diabetes often leads to serious complications that affect various tissues in the body. Elevated levels of glucose enhance protein glycation with formation of AGEs. The accumulation of AGEs as well as ROS production contributed to diabetic complications.
Many studies illustrated that complications associated with DM can be prevented, reduced or even reversed through proper control of blood glucose levels by using exogenous insulin. However, administration of exogenous insulin cannot mimic precise pancreatic beta cell regulation of glucose homeostasis and frequently associated with severe hypoglycaemic episodes.
BM-MSCs have been extensively examined for their potential to immunomodulation, tissue repair and generation of IPCs reducing blood glucose level. Beside their anti-diabetic effect, BM-MSCs can home to the injured tissues and exert ameliorative influence via direct differentiation into a variety of cell types and integration into tissues, or release of paracrine factors that enhance the regeneration by stimulation of proliferation and differentiation of the tissue-intrinsic stem cells. These secreted factors also can inhibit oxidative stress, inflammation, apoptosis and fibrosis of damaged tissues.
So the aim of this study was to examine the effect of BM-MSCs on the lingual papillae of diabetic albino rats in comparison to insulin.
The current study was carried out on 56 male Wistar albino rats weighing between 200-250gm. The rats were equally divided into 4 groups:
1) Control group (Gp I):
This group included normal healthy rats that received no drug.
2) Diabetic group (Gp II):
Rats were given a single intra-peritoneal injection of STZ (40mg/kg BW). Diabetes was defined as a FBG reading of greater than 250mg/dl after 72hr of STZ injection.
3) BM-MSCs treated diabetic group (Gp III):
Rats were injected by STZ as Gp II then after diabetes confirmation; rats were given a single intravenous injection of BM-MSCs (1x106 cells) through tail vein.
4) Insulin treated diabetic group (Gp IV):
Rats were injected by STZ as Gp II then after diabetes confirmation; rats were daily given a single subcutaneous injection of insulin (5IU/kg BW) for 4weeks.
Four weeks after diabetes confirmation, the tongues were immediately dissected, where half of the tongue specimens from all groups processed, stained by H&E stain for routine histological examination and Anti-PCNA stain for investigation of cell proliferation. FM was used for detection of homing of injected labeled BM-MSCs in rats’ lingual papillae. While the other half examined by SEM for assessment of surface topography.
I) Light microscopic results for H&E stained sections:
Examination of H&E stained sections of control group revealed that the different type of lingual papillae consisted of orthokeratinized stratified squamous epithelium with well-formed c.t central core. All types of filiform papillae had convex and concave sides. Simple conical papillae appeared as conical pointed projections, Giant conical papillae as sharp conical papillae being larger than simple conical papillae while true filiform papillae were long and slender with a thread like shape. Fungiform papillae manifested the typical mushroom like shape with single well-defined barrel-shaped taste bud. Circumvallate papilla revealed as single inverted cone-shaped and was surrounded by a well-developed deep trough with numerous taste buds in the epithelial wall of the trough. Foliate papillae appeared as several parallel ridges that were separated by narrow and deep troughs with several taste buds. Lobules of Von Ebner salivary glands were separated by c.t septa and located under the circumvallate and foliate papillae.
In diabetic group, the papillae did not show their characteristic shape and all appeared narrowed and shortened. The epithelial covering were thinned and revealed numerous cytoplasmic vacuoles and was covered by torn and separated keratin layer. Distorted and ill-defined taste buds were shown in gustatory papillae and in circumvallate and foliate papillae seemed to be fewer in number than control group. Loose and degenerated c.t cores were demonstrated with dilated b.vs and inflammatory cells infiltration. Von Ebner salivary glands showed shrunken acini with presence of numerous cytoplasmic vacuoles.
In both BM-MSCs and insulin treated diabetic groups, the lingual papillae displayed apparent improvements in form of increasing in epithelial covering and lamina propria thickness, fewer cytoplasmic vaculations within the epithelium, less detached keratin layer, nearly normal taste buds in morphology and number as well as less degenerated c.t with fewer inflammatory cells infiltrate. In addition, the acini and ducts of Von Ebner salivary glands appeared nearly normal. These improvements appeared to be more obvious in insulin than BM-MSCs treated group.
II) Light microscopic results for Anti-PCNA immunohistochemical stained sections:
The epithelium of filiform and fungiform papillae of control group revealed obviously detectable positive reactions in all basal and some para-basal cells with positive basal cells of fungiform papillae taste buds. While the c.t showed less frequently positive reactions.
In diabetic group, only some positive basal cells were detected in the epithelium with negative reaction in taste bud cells and scarce positive c.t cells.
In both treated group, the epithelium of the papillae showed positive reactions in almost all basal, few para-basal cell and taste bud basal cells with less apparently positive c.t cells.
III) Fluorescent microscopic results:
The phase contrast fluorescent microscopic examination of BM-MSCs treated diabetic group showed red fluorescent PKH26 labeled cells in the epithelium, c.t of all papillae and taste buds of fungiform, circumvallate and foliate papillae with no fluorescence in all lingual papillae of other groups.
IV) Scanning electron microscopic results:
The control group revealed that simple conical papillae appeared as numerous conical projections covering the anterior two thirds of the tongue body and arranged in parallel rows that curved backward towards the tongue root. Giant conical papillae that were present in the intermolar eminence, appeared large conical in shape with wide base and divided tips. True filiform papillae were seen in the posterior one thirds of the tongue body and appeared closely packed thread like in shape with different directions. Fungiform papillae appeared cauliflower in shape with centrally located well-defined taste pore. Circumvallate papilla showed central papillary structure with tapered end and was surrounded by horse shoe shaped elevated flanking papillary structure and narrow trough. Foliate papillae appeared as 3-4 series of parallel ridges separated by narrow grooves.
In diabetic group, all lingual papillae lost their characteristic shape that appeared narrowed and shortened. Detectable decreased simple conical and true filiform papillary density with atrophic giant conical papillae’ tips were seen. In addition, fungiform papillae were atrophied with wrinkled surface and hardly detected taste pore. While circumvallate and foliate papillae were shrunken and surrounded by obviously widened troughs.
In both treated groups, all papillae restored their normal morphological picture. Meanwhile, in BM-MSCs treated group, simple conical papillae demonstrated increased interpapillary regions in some areas, as well, some giant papillae showed atrophied tips. Circumvallate and foliate papillae were surrounded by slightly widened troughs. While in insulin treated group, the central papillary part of circumvallate papillae seemed to be bulging.
V) Statistical results:
A) Fasting blood glucose level:
The mean FBG level increased significantly after 3D of STZ administration, confirming the diabetic state. In diabetic group, this increase was followed by further gradual significant increase along the experimental period. While in both treated groups, the increased mean FBG level was followed by a significant decrease over weeks, being significantly lower values than diabetic group.
However, in insulin treated group, the mean FBG level was significantly lower than BM-MSCs treated group during the course of the study and showed insignificant changes in their values compared to control one at the end of the experiment.
B) Body weight:
Normal rats continued to grow throughout the experimental period increasing in their mean BW, while in diabetic rats, the decreasing in their weights was a statistically significant.
According to the treated groups, mean BW of all rats decreased significantly in the first week after diabetes confirmation. Then, in BM-MSCs treated group, there was an insignificant increase in mean BW at the end of the experiment. However, these increased values were significantly higher than diabetic rats. In insulin treated group, the mean BW increased significantly throughout the remaining period of the experiment, being significantly higher than BM-MSCs treated group but lower than control rats.
C) Anti-PCNA positive cells:
In the epithelial covering of all types of filiform papillae, there was a statistically significant difference in mean number of Anti-PCNA positive cells between the different groups. Gp I showed the highest values then Gp IV followed by Gp III. However, Gp II showed the lowest mean number of Anti-PCNA positive cells. While in fungiform papillae, there was an insignificant difference between Gp I and Gp IV; both showed the significantly highest mean number of Anti-PCNA positive cells, followed by Gp III that showed significant difference from Gp I and insignificant difference from Gp IV. Gp II showed the significantly lowest mean number of Anti-PCNA positive cells.
D) PKH26 labeled cells:
There was a statistically significant difference in mean number of PKH26 labeled cells at different papillae within Gp III. Circumvallate papillae showed the highest values followed by foliate papillae. True filiform papillae showed lower number, then simple conical, then giant conical papillae. Fungiform papillae showed the significantly lowest values.