Adipose-Derived Stem Cells' Secretome Attenuates Lesion Size and Parasite Loading in Leishmaniasis Caused by Leishmania Major in Mice

Abstract

Background: Stem cell-derived secretome (SE) released into the extracellular space contributes to tissue repair. The present study aimed to investigate the impact of isolated secretome (SE) from adipose-derived mesenchymal stem cells (ASCs) on Leishmania major (L. major) lesions in BALB/c mice.

Methods: This experimental study was conducted at Ahvaz University of Medical Sciences (Ahvaz, Iran) in 2021. Forty female BALB/c mice were infected with stationary phase promastigotes through intradermal injection in the bottom of their tail and randomly divided into four groups (n=10 per group). The mice were given SE (20 mg/mL), either alone or in combination with Glucantime (GC, 20 mg/mL/Kg), meglumine antimoniate (20 mg/mL/Kg) for the GC group, and phosphate-buffered saline (PBS) for the control group. After eight weeks, the lesion size, histopathology, the levels of Interleukin 10 (IL-10), and Interleukin 12 (IL-12) were assessed. For the comparison of values between groups, the parametric one-way ANOVA was used to assess statistical significance.

Results: At the end of the experiment, the mice that received SE had smaller lesions (4.56±0.83 mm versus 3.62±0.59 mm, P=0.092), lower levels of IL-10 (66.5±9.7 pg/mL versus 285.4±25.2 pg/mL, P<0.001), and higher levels of IL-12 (152.2±14.2 pg/mL versus 24.2±4.4 pg/mL, P<0.001) than the control. Histopathology findings revealed that mice treated with SE had a lower parasite burden in lesions and spleen than the control group.

Conclusion: The current study demonstrated that ADSC-derived SE could protect mice infected with L. major against leishmaniasis.

Keywords: Adipose-derived mesenchymal stem cells; Cytokines; Leishmania; Mice; Secretome; Wound.

Figure 1

Characterization of ASCs is shown by flow cytometry. CD44, CD73, CD90, and mesenchymal stem cell surface markers were highly expressed. CD34, hematopoietic stem cell surface markers indicated low expression.

Figure 2

Characterization of ASCs is illustrated using histochemistry. The Alizarin Red (A) and Oil Red O (B) staining indicated the osteogenic and adipogenicity differentiation potential of ASCs.

Figure 3

Treatment of cutaneous leishmaniasis wounds with Glucantime (GC), Secretome (SE), and Secretome+Glucantime (SE+GC) and comparing with the control group on days 7, 28, and 56 days after treatment. On day 7, the size of the wounds in the control and treatment groups did not show significant changes. On days 28 and 56, the size of the wounds in the experimental groups was smaller than the control group.

Figure 4

Average sizes of CL in different groups (mean±SD). GC: Glucantime; SE: Secretome; SE+GC: Secretome+Glucantime; *Compared with the control group (P<0.05); **P<0.01

Figure 5

Parasites (arrows) were observed in the spleen of the mice of the control group (A) and GC+SE (B) groups. Magnifications: ×400; GC: Glucantime; SE: Secretome

Figure 6

Serum concentrations of IL-10 and IL-12 in different groups analyzed with the Mann-Whitney U test (mean±SD). GC: Glucantime; SE: Secretome; SE+GC: Secretom+Glucantime; *P<0.01; **P<0.001; #P<0.05; * and # show comparison to the control and GC groups