Leucocyte-derived Inflammation Ratios, Red-cell Distribution Width and Platelet Size Indices in Wistar Rats Given Aqueous Justicia carnea Leaf Extract

Abstract

Background: Ratios derived from the leucocyte differential and the platelet count, together with red-cell and platelet size-distribution indices, are inexpensive markers of systemic inflammation and of the activity of the bone marrow. They have not been applied to Justicia carnea Lindl. (Acanthaceae), a leaf preparation consumed widely in Nigeria as a blood tonic. Aim: To determine whether repeated oral intake of the aqueous leaf extract alters the leucocyte differential, leucocyte-derived inflammation ratios, red-cell distribution width or platelet size indices in healthy rats. Methods: Male Wistar rats were given distilled water (n = 4) or the extract at 200, 400, 600 or 800 mg/kg (n = 5 per group) by gavage once daily for 14 days. Blood from 14 rats was analysed on a three-part impedance analyser. Lymphocyte, mid-sized cell (MID) and granulocyte counts and proportions were recorded, and the granulocyte-to-lymphocyte ratio (GLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-MID ratio (LMR) and systemic immune-inflammation index (SII) were calculated. Red-cell distribution width (RDW-CV, RDW-SD), platelet distribution width (PDW), platelet large-cell ratio (P-LCR) and platelet large-cell count (P-LCC) were expressed relative to the control mean. Groups were compared by ANOVA with Dunnett’s test, the Kruskal–Wallis test and a permutation test, with Benjamini–Hochberg adjustment across parameters; dose trends were assessed with the Jonckheere–Terpstra test. Results: The proportions of lymphocytes (64.3–69.7%) and granulocytes (16.1–24.8%) were unchanged (p = 0.925 and 0.795), and GLR, PLR, LMR and SII did not differ from control (p = 0.324–0.727). Lymphocyte counts were higher in all treated groups (4.30–6.50 vs 2.97 × 10³/µL; Hedges’ g = 0.58–1.99) without reaching significance. RDW did not increase at any dose (RDW-CV 74–92% of control). P-LCC differed between groups (ANOVA p = 0.019; permutation p = 0.022) and was raised at 800 mg/kg (411% of control; Dunnett p = 0.016), whereas PDW was unchanged; this was the only nominally significant result and did not remain significant after adjustment for the 15 parameters tested (adjusted p = 0.284). Conclusion: The aqueous leaf extract produced no haematological signs of systemic inflammation or disordered erythropoiesis at 200–800 mg/kg. The increase in large platelets at the highest dose, without a change in PDW, suggests stimulated thrombopoiesis rather than platelet activation and warrants confirmation.