Balanced TH1 and TH2 immunopotentiating effects of silicates partly containing nanoparticles present in calcined serpentine

Our plain-English summary of Balanced TH1 and TH2 immunopotentiating effects of silicates partly containing nanoparticles present in calcined serpentine, by A. Elahi, Y. Sharma, S. Bashir, et al (Journal of Immunotoxicology, 2016).

The study

• Authors: A. Elahi, Y. Sharma, S. Bashir, F. Khan
• Journal: Journal of Immunotoxicology
• Published: 2016;13(3):335-48
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Calcined Serpentine (CS) is used in various formulations of alternative systems of medicine as a tonic to vital organs and as an anti-inflammatory agent. The process of calcination or incineration is believed to render non-toxic, gently absorbable, adaptable and digestible properties to the mineral compounds. The present study characterized CS and also evaluated its immunostimulatory potential. CS was characterized by using transmission electron microscopy (TEM), X-ray powder diffraction, atomic absorption spectroscopy and CHNS analysis. The characterized CS was further evaluated for its immunomodulatory potential in Swiss mice. X-Ray diffraction analysis revealed that the CS contained silicates of magnesium, calcium and iron as major minerals. Elemental composition and heavy metal analyses showed a presence of various inorganic elements/heavy metals, albeit at levels well below daily permissive intake values. TEM analysis of the test CS revealed a presence of nano particles with an average size of 10-20 nm (≈ 26% of total material). Oral administration of CS to mice at 50, 75, 100 or 200 μg/kg body weight for 10 days led to enhanced levels of total IgG, IgG1, IgG2a and IgG2b in ovalbumin-immunized mice as well as ex vivo lymphocyte proliferation and levels of TH1 (IL-2, IFNγ) and TH2 (IL-4, IL-10) cytokines produced by their cultured splenocytes. Similarly, CS treatment resulted in enhanced delayed-type hypersensitivity responses in GRBC-primed hosts. CS also activated host peritoneal macrophages, as indicated by increases in phagocytic activity and in TLR-2, CD80 and CD86 expression. The CS did not affect liver, kidney and spleen histology. Taken together, the results indicated that absorbed CS was stimulatory of host cell-mediated immune responses. It is hypothesized for now that the immunomodulatory effect of CS may have been due, in part, to a presence of nanoparticles on the CS; further study is required to validate this viewpoint.

In plain English

In this animal laboratory study, the authors characterised calcined serpentine (CS), a mineral preparation used in Unani traditional medicine, and tested its effects on immune responses in male Swiss mice. X-ray diffraction indicated silicates of magnesium, calcium and iron; transmission electron microscopy showed particles ranging from 1 to 60 nm, with the maximum number in the 10-20 nm range, and the filtrate contained nanoparticles equal to 26% by weight of the original total CS. Lead was 168.93 mg/kg, mercury 1.10 mg/kg; cadmium and arsenic were not detected. Mice were gavaged daily for 10 days with four CS doses. Compared with controls, treated mice had higher ovalbumin-specific IgG and IgG subclasses, larger delayed-type hypersensitivity responses (significantly enhanced at the three highest doses), and a higher macrophage phagocytic rate with raised TLR-2, CD80 and CD86 and lowered TLR-4. Spleen cells from these mice, stimulated ex vivo with ovalbumin or ConA, proliferated more and released more TH1 (IL-2, IFN) and TH2 (IL-4, IL-10) cytokines; no increases occurred without stimulation. No significant differences were found in macrophage nitric oxide or in stimulated splenocyte IL-1 and TNF; liver, kidney and spleen histology showed no injury at the highest dose. The authors concluded that CS exhibited immunomodulatory potential and appeared able to stimulate both innate and adaptive immunity in the treated rodent host.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Experimental animal study (mouse in vivo dosing with ex vivo assays) combined with physico-chemical characterisation of the test material and an everted rat gut sac absorption experiment
• Who was studied: Male Swiss mice, 6-8 weeks old, 20-25 g, five mice per treatment group, housed at Jamia Hamdard, New Delhi, India; small intestine from a fasted naive Wistar rat was used for the gut sac experiment
• Exposure: Calcined serpentine (a calcined magnesium/calcium/iron silicate mineral partly consisting of nano-sized material) given by oral gavage daily for 10 days at four dose levels (50, 75, 100 and 200 per kg body weight, printed as mg/kg in the article text)
• Main results:
  • The filtrate prepared from the CS contained nanoparticles equal to 26% by weight of the original total CS weight; particles were spherical and ranged from 1 to 60 nm, with the maximum number in the 10-20 nm range
  • Size distribution analysis showed the largest number of particles in the 10-20 nm range
  • X-ray diffraction identified the chief mineral constituents of the CS, all silicates of magnesium, calcium and iron
  • Heavy metal analysis of the CS found 168.93 mg lead/kg and 1.10 mg mercury/kg, with cadmium and arsenic not detected
  • In ovalbumin-immunised mice, anti-OVA IgG was significantly raised at all four CS doses up to Day 60 after primary immunisation (p less than 0.01 versus control)
  • Delayed-type hypersensitivity responses were significantly enhanced only at the three highest doses; the footpad values were 15.60 ± 2.12 in controls versus 18.52 ± 5.78, 29.42 ± 0.03, 37.52 ± 1.05 and 35.94 ± 1.81 in the 50, 75, 100 and 200 per kg groups
  • Splenocytes from CS-treated, OVA-immunised mice proliferated more and released more TH1 and TH2 cytokines than control cells when stimulated ex vivo with OVA or ConA; no spontaneous cytokine increases occurred without stimulation
  • Peritoneal macrophage phagocytic rate was 18.30 ± 2.02% in controls versus 27.30 ± 1.45%, 33.60 ± 1.76%, 38.30 ± 2.18% and 33.00 ± 2.08% in the CS groups (all significantly increased)
  • Macrophage TLR-2 expression rose with CS treatment (control 3.3%; 50 group 22.7%, 75 group 35.3%, 100 group 9.5%, 200 group 5.5%) while TLR-4 expression fell at all doses (control 16.6%)
  • Stimulated splenocytes from CS-treated mice showed no significant changes from control values in the pro-inflammatory cytokines IL-1 or TNF
  • Nitric oxide production by peritoneal macrophages, spontaneous or LPS-induced, showed no significant change with CS treatment
  • No morphological injury was seen in liver, kidney or spleen of mice given the highest dose for 10 days
• The authors' conclusion: The authors concluded that calcined serpentine exhibited immunomodulatory potential and appeared able to stimulate both innate and adaptive immunity in the treated rodent host, and suggested its possible use as an adjuvant should be explored in future
• Limitations the authors state:
  • The authors noted the absence of a conventional dose-response relationship for most endpoints
  • The authors stated that further studies are needed to clarify whether CS favours TH1 or TH2 responses
  • The authors said the attribution of the effects to nanoparticles was only a hypothesis needing validation
  • The authors acknowledged that changes in intestinal tissue viability could have limited the everted gut sac analysis, though they argued this was not a confounder over the 45-minute period
  • The authors noted that further post-exposure analyses at later timepoints would be required to verify the thymus and spleen weight findings

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Silicate, Serpentine Group, Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Cytokine, Macrophage, Histology.

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