Abstract

Background:
During innate immunity, peritoneal macrophages orchestrate early nitro-oxidative and chemokine responses, and their polarization is influenced by mouse strain–dependent metabolic programs. Tradescantia spathacea is a medicinal plant with reported anti-inflammatory and antioxidant properties; however, its effects on macrophage nitro-oxidative and chemokine responses remain unclear.

Aim:
To investigate the effects of a methanolic extract of T. spathacea (MET.s) on nitro-oxidative and chemokine responses in peritoneal macrophages (PMs) from BALB/c and C57BL/6 mice.

Methods:
LPS-elicited PMs were obtained from female BALB/c and C57BL/6 mice. The cytotoxicity and half-maximal inhibitory concentrations (IC50) of MET.s were determined by MTT assay. Nitric oxide (NO) production was quantified using the Griess reaction. Gene expression of iNOS, ARGII, TGF-β, MCP, and MIP was evaluated by real-time PCR in PMs stimulated with IL-4 or LPS, alone or in combination with strain-specific IC₅₀ concentrations of MET.s.

Results:
MET.s did not reduce mitochondrial activity in either strain; IC50 values were 4.76 µg/mL for BALB/c and 81.92 µg/mL for C57BL/6 PMs. BALB/c PMs exhibited a modest but significant increase in NO at 50 µg/mL, whereas C57BL/6 PMs exhibited decreased NO at the same concentration, inverting the expected strain pattern. In BALB/c PMs, MET.s alone or in combination with LPS or IL-4 favored iNOS and TGF-β expression, suggesting a pro-nitro-oxidative yet regulated profile. In C57BL/6 PMs, LPS+MET.s downregulated iNOS while upregulating ARGII and TGF-β, while MET.s selectively increased MIP with concurrent MCP reduction in both LPS- and IL-4-driven conditions, indicating a shift towards a balanced chemokine-mediated recruitment.

Conclusion:
The methanolic extract of T. spathacea exerts non-cytotoxic, strain-dependent immunomodulatory effects on peritoneal macrophages, reshaping nitro-oxidative output and chemokine gene expression to favor a context-dependent balance between activation and regulation. These findings support its potential as a natural immunomodulator and justify further mechanistic and in vivo studies.

Key words: BALB/c; C57BL/6; Chemokines; Peritoneal macrophages; Tradescantia spathacea.