Vitamin D3 supplementation could ameliorate the inflammatory and redox status in the muscular phase of trichinellosis

Nutritional supplements, particularly vitamin D, have been widely used worldwide in the treatment of various
infections, including parasites. This study aimed to evaluate the potential effects of vitamin D3 supplementation
on the muscular phase of trichinellosis in experimental animals. Mice were divided as follows: (group I): infected
untreated, (group IIa) infected and treated with vitamin D3 for 12 doses beginning 2 weeks before infection and
continuing after infection, (group IIb) infected and treated with vitamin D3 for 8 doses beginning on the same
day of infection, (group III) normal control, (group IVa) which received vitamin D3 for 12 doses and (group IVb)
which received vitamin D3 for 8 doses. Mice were sacrificed 35 days after infection and total muscle larval count,
and histopathological examination of muscle samples with immunohistochemical staining of cyclooxygenase 2
(COX2) and inducible nitric oxide synthase (iNOS) were performed. Muscle relative cathelicidin mRNA expression
was assessed, as well as serum levels of muscle enzymes CK and LDH, interleukin-4 (IL-4), IL-10, IL-17 and
interferon-gamma (INF-γ). Vitamin D3 supplementation significantly reduced muscle larval count, inflammatory
cellular infiltration, COX2 and iNOS expression. Furthermore, it increased cathelicidin gene expression, decreased
serum levels of CK and LDH and affected serum cytokine levels, increasing serum IL-4 and IL10 levels while
decreasing serum INF γ and IL-17. In conclusion, vitamin D3 supplementation has favorable outcomes on the
muscle phase of trichinellosis, including anti-inflammatory, antioxidant, and immunomodulatory effects.