Can Intranasal Administration of Adipose-Derived Stem Cells Reach and Affect the Histological Structure of Distant Organs of Aged Wistar Rat?

Abstract

Introduction: Stem cell therapy is a highly promising strategy in various degenerative diseases. Intranasal administration of stem cells could be considered as a non-invasive treatment option. However, there is great debate concerning the ability of stem cells to reach distant organs. It is also unclear in such a case if they can alleviate age-related structural changes in these organs.

Aim: The aim of this study is to evaluate the ability of intranasal administration of adipose-derived stem cells (ADSCs) to reach distant organs of rats at different time intervals and to investigate their effects on age-related structural changes in these organs.

Materials and methods: Forty-nine female Wistar rats were used in this study, seven of which were adults (6-month-old) and 42 were aged (2-year-old). Rats were divided into three-groups: Group-I (adult control), Group-II (aged), and Group-III (aged ADSCs treated). Rats of Groups I and II were sacrificed after 15 days from the beginning of the experiment. Rats of Group III were treated with intranasal ADSCs and were sacrificed after 2-h, 1-day, 3-day, 5-day, and 15-day. Heart, liver, kidney, and spleen specimens were collected and processed for H and E, CD105 immunohistochemistry, and immunofluorescent techniques. Morphometric study and statistical analysis were performed.

Results: ADSCs appeared in all organs examined after 2-h of intranasal administration. Their maximum presence was detected after 3-day of administration, after which their immunofluorescence gradually decreased and nearly disappeared from these organs by the 15^th day. Improvement of some age-related deterioration in the structure of the kidney and liver occurred at day 5 after intranasal administration.

Conclusions: ADSCs effectively reached the heart, liver, kidney, and spleen after intranasal administration. ADSCs ameliorated some age-related changes in these organs.

Keywords: Adipose-derived stem cells; aging process; cell-based therapy; immunofluorescent techniques; intranasal stem cells; mesenchymal stem cells.

Figure 1

Flow cytometric histograms of rat adipose-derived stem cells are displayed using antibodies directed against CD44, CD45 and CD73. Most cells are positive for CD44, CD73 and negative for CD45

Figure 2

Green fluorescence of PKH-26 labelled stem cells from all organs at different time-intervals. Green fluorescence is seen in all organs after two hours from intranasal administration of stem cells. Maximum fluorescence is seen in all organs at day three and day five which is most prominent in kidney and liver. Gradual decrease of fluorescence is noticed at day five which disappear at day 15 from all organs expect the spleen. In aged group, negative reaction is seen in all organs. Immunofluorescence photomicrographs ×100 scale bar: 200 μm

Figure 3

Immunohistochemical stain for CD105 of different organs at different time-intervals. Insets: positive reaction inside the cells. ([↑]: positive reaction in endothelium of blood capillaries. [▴]: positive reaction inside cells of cardiac myocytes, renal tubules, hepatocytes and cells of the spleen). Immunoperoxidase ×400, insets ×1000, scale bar: 50μm

Histogram 1

Showing the mean area percentage of CD105 in different organs in different groups

Figure 4

Structure of myocardium in different groups. ([↑]: oval vesicular nuclei, [▴] blood capillaries between cardiac myocytes, [curved arrow] Pyknotic nuclei) H and E ×400

Figure 5

Kidney sections of different groups. ([*]: glomerular space, [PCT]: Proximal convoluted tubules, [DCT]: Distal convoluted tubules, [V]: Vacuolated cells, [C]: Cast, [↑]: Mesangial cells, [▴]: Congested blood capillaries, [curved arrow]: pyknotic nuclei) H and E ×400

Figure 6

Liver sections of different groups. ([↑]: rounded vesicular nuclei, [S]: congested hepatic sinusoids, [*]: inflammatory cells, [▴]: pyknotic nuclei, [Δ] vacuolated hepatocytes) H and E ×400

Figure 7

Spleen sections in different groups. ([WP]: White pulp, [RP]: Red pulp, [GC]: germinal center, [FA]: follicular artery, [*]: pale less cellular parts of red pulp) H and E (adult, aged I and adipose-derived stem cells subgroups ×100) (aged II ×400)