الفهرس 
STRUCTURE AND FUNCTION OF THE LIVER AND SMALL INTESTINEOnly 14 pages are availabe for public view
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Abstract
A
ge-related changes occur in all the body’s cells, tissues, and organs, and these changes affect the functions of all body systems. These alterations appear slowly and over a long period. Moreover, the regenerative capacity of most tissues declines with age. Platelet-rich plasma (PRP) contains beneficial growth factors for tissue regeneration, repair, and deaccelerating the aging process.
The current study was carried out to investigate the structural changes that might occur during normal aging on the liver and jejunum part of the small intestine and the possible effect of PRP intraperitoneal injection on adult and aged male rats. The experiment was conducted on forty-two male albino rats and classified according to age into adult and aged groups:
Adult male rats (300 -350 g), their age range between 6-8 months and this is equal 18-20 years in human age.
Aged male rats (570-660 g), their age range between 12-24 months and this is equal 45-60 years in human age.
After the acclimatization period, the animals were randomly divided into four groups: group I (control adult): Included 14 rats that were further subdivided into 2 equal subgroups: subgroup Ia: untreated rats and subgroup Ib: rats were injected by sterile saline (0.5 ml/kg by intraperitoneal injection twice/week). group II (control aged): Included 14 rats that further subdivided into 2 similar subgroups as group I, group III (adult with PRP): Included 7 rats that received intraperitoneal injection of PRP (0.5 mL/kg twice/week), group IV (aged with PRP): Included 7 rats that received intraperitoneal injection of PRP as group III.
All experimental animals were sacrificed at the end of the experiment, after 21 days by cervical dislocation after ether inhalation. The liver and Jejunum of all groups were enucleated and prepared for histological and immune-histochemical studies. Moreover, morphometric, and statistical measurements were done.
Liver:
Examination of H&E-stained sections of adult groups (I&III) showed hepatocytes with acidophilic cytoplasm, single central rounded vesicular nuclei and some of the cells were binucleated. Hepatocytes were separated by blood sinusoids, which were lined by flat endothelial cells. The portal areas also were noticed at the periphery of the classic hepatic lobules.
Examination of H&E-stained sections of the control aged group (II) showed distortion and marked congestion of sinusoids with areas of hemorrhage and mononuclear infiltration. Most of the hepatocytes were vacuolated while others appeared with deep acidophilic cytoplasm and deeply stained nuclei.
On the other hand, examination of H&E-stained sections of the aged with PRP group (IV) showed that hepatic lobules architecture was preserved with few mononuclear cellular infiltrations surrounding the portal tracts. Most hepatocytes have rounded, vesicular nuclei with an apparent decrease in binucleated cells.
In PAS-stained sections of the adult with PRP group (III) the cytoplasm of the hepatocytes showed apparent normal content of PAS-positive granules as that seen in the control adult group (I).
Examination of PAS-stained sections of group II showed a significant increase in the mean area percentage of glycogen in zone 3 of liver parenchyma when compared to groups (I, III & IV).
On the other hand, there was a significant decrease (P ≤ 0.05) in the mean area percentage of glycogen of the aged with PRP group (IV) when compared to group (II).
Additionally, Masson’s trichrome stained sections revealed that there was a significant increase in the mean area percentage of collagen fibers of group II when compared to other groups (I, III & IV). However, there was a significant decrease in the mean area percentage of collagen fibers of the PRP group (IV) when compared to the control group (II). Moreover, there was a significant decrease (P ≤ 0.05) in the mean area percentage of collagen fiber PRP- adult group (III) when compared to aged groups (II&IV).
Electron microscopic examination of the adult groups (I&III) showed that the hepatocytes appeared studded with mitochondria, rough endoplasmic reticulum (rER), and euchromatic nuclei. While in group II the hepatocytes showed multiple electron-lucent lipid droplets and irregular small nuclei with dilated cristae of rER and scattered α glycogen rosettes. In addition, perisinusoidal spaces showed thickening of endothelial cells and collagen deposition.
In the aged with PRP group (IV) hepatocytes showed regular, rounded, euchromatic nuclei and prominent nucleoli with abundant mitochondria surrounding the nuclei and rER attached to the outer nuclear membrane. Moreover, Hepatic sinusoids were lined by flat endothelial cells with fewer perisinusoidal collagen deposits.
Jejunum:
Examination of H&E-stained sections of adult groups (I & III) showed the mucosa with long and slender villi covered by columnar absorbing cells joined to each other. The crypts of Lieberkühn were noticed lined by enterocytes with basal vesicular nuclei and a few scattered intraepithelial lymphocytes. Lamina propria contained few mononuclear cellular infiltrations.
On the other hand, examination of H&E-stained sections of the jejunal wall of the control aged group (II) showed the jejunal villi distorted and short. There was an increase in spacing between adjacent enterocytes with sloughed villi tips and disruption of their surface epithelium. Moreover, the intestinal crypts showed excessive mononuclear cell infiltration in the lamina propria with many intraepithelial lymphocytes seen in between the enterocytes.
In contrast, the aged with PRP group (IV) showed few jejunal villi with sloughed tips and decreasing in intercellular spaces between adjacent enterocytes. Moreover, the intestinal crypts displayed few intraepithelial lymphocytes and mononuclear cell infiltration in the lamina propria.
PAS examination sections of adult groups (I & III) displayed positive PAS reaction in the surface brush border and in the apical distended portion of goblet cells. Whereas the villi of group II showed partial loss of acidophilic brush border and an apparent reduction of mucin granules in some of the goblet cells. In aged with PRP group (IV) showed an intact brush border with some goblet cells with PAS-positive magenta mucin content.
Additionally, Masson’s trichrome stained sections of adult groups (I &III) showed few mucosal and submucosal collagen fibers. However, there was a non-significant decrease (P > 0.05) in the area percentage of collagen of the submucosa of group III when compared to group I.
In contrast, aged groups (II &IV) showed many collagen fibers in mucosa and submucosa. Moreover, there was a significant decrease (P ≤ 0.05) in the area percentage of collagen of the submucosa of the aged with PRP group (IV) when compared to the control aged group (II).
In addition, there was a significant decrease (P ≤ 0.05) in the muscle thickness of group (II) when compared to other groups. While the jejunal wall showed a significant increase (P ≤ 0.05) in the muscle thickness of (group IV) when compared to (group II).
There was a significant increase (P ≤ 0.05) in the mean brush border thickness of the adult with PRP group (III) when compared to the aged groups. On the other hand, there was a significant decrease (P ≤ 0.05) in the mean brush border thickness of the aged group (II) when compared to adult groups.
Immunohistochemical staining for anti-claudin-2 polyclonal antibody showed a significant increase (P<0.05) in the area percentage in aged groups (II & IV) as compared to that of the adult groups (I & III). Whereas the adult with PRP group (III) showed a significant decrease (P ≤ 0.05) in the area percentage of anti-claudin-2 polyclonal antibody when compared to other groups. However, there was a non-significant decrease (P > 0.05) in the area percentage of anti-claudin-2 polyclonal antibody of the aged-PRP group (IV) when compared to the control aged group (II).
CONCLUSION AND RECOMMENDATIONS
Conclusion:
T
he use of intraperitoneal injection of PRP proved to be successful in improvement and decelerating the aging process in the liver and jejunum.
Recommendations:
• More studies are needed to understand factors affecting PRP with aging and the possible effect of PRP injections from young donors to aged individuals.
• Future work are needed to assess the potential improvement and regenerative effect of long-term PRP injections on aged liver and jejunum.
• More investigations are needed to clarify the optimal PRP concentration that allows for maximum enhancement of healing and regeneration.