Gelam honey has a protective effect against lipopolysaccharide (LPS)-induced organ failure

Abstract

Gelam honey exerts anti-inflammatory and antioxidant activities and is thought to have potent effects in reducing infections and healing wounds. The aim of this study was to investigate the effects of intravenously-injected Gelam honey in protecting organs from lethal doses of lipopolysaccharide (LPS). Six groups of rabbits (N = 6) were used in this study. Two groups acted as controls and received only saline and no LPS injections. For the test groups, 1 mL honey (500 mg/kg in saline) was intravenously injected into two groups (treated), while saline (1 mL) was injected into the other two groups (untreated); after 1 h, all four test groups were intravenously-injected with LPS (0.5 mg/kg). Eight hours after the LPS injection, blood and organs were collected from three groups (one from each treatment stream) and blood parameters were measured and biochemical tests, histopathology, and myeloperoxidase assessment were performed. For survival rate tests, rabbits from the remaining three groups were monitored over a 2-week period. Treatment with honey showed protective effects on organs through the improvement of organ blood parameters, reduced infiltration of neutrophils, and decreased myeloperoxidase activity. Honey-treated rabbits also showed reduced mortality after LPS injection compared with untreated rabbits. Honey may have a therapeutic effect in protecting organs during inflammatory diseases.

Keywords: biochemical tests; honey; inflammation; lipopolysaccharide; myeloperoxidase; rabbits.

Figure 1

Effect of honey on neutrophil infiltration into lung tissues induced by a lethal dose of lipopolysaccharide (LPS). Myeloperoxidase (MPO) activity was measured in all groups (n = 6 per group) 8 h after LPS injection. MPO activity was significantly higher in the untreated (saline + LPS 0.5 mg/kg) group than in the treated (honey, 500 mg/kg + LPS 0.5 mg/kg) group. *** P < 0.002.

Figure 2

(A) Immune-cell infiltration and tissue damage in the lungs of rabbits from the untreated group 8 h after LPS injection; (B) Immune-cell infiltration and tissue damage in the lungs of rabbits from the honey-treated group 8 h after LPS injection; (C) Normal lung tissues in rabbits treated with saline. Hematoxylin and eosin staining; magnification 10×; scale bar, 30 μm.

Figure 3

The effect of honey on the survival of rabbits injected with LPS (0.5 mg/kg). Rabbits in all three groups (n = 6 per group) received 1 mL injections of LPS into the ear vein. The survival rates in the untreated and honey-treated (60, 300, and 600 mg/kg) groups injected with 0.5 mg/kg LPS are shown as black triangles and black squares, respectively. Control rabbits received saline only (black circles). Honey was administered daily for 3 days after LPS treatment. Kaplan–Meier analysis showed significantly better survival rates in the honey-treated group (500 mg/kg + LPS) than in the untreated LPS group (LPS). *** P < 0.005.