The Effects of Probiotic Bacillus Spores on Dexamethasone-Treated Rats

Abstract

Glucocorticoids are effective anti-inflammatory and immunosuppressive agents. Long-term exposure is associated with multiple metabolic side effects. Spore-forming probiotic bacteria have shown modulatory properties regarding glycolipid metabolism and inflammation. The aim of this study was to evaluate, for the first time, the effects of Bacillus species spores (B. licheniformis, B. indicus, B. subtilis, B. clausii, and B. coagulans) alone and in combination with metformin against dexamethasone-induced systemic disturbances. A total of 30 rats were randomly divided into 5 groups: group 1 served as control (CONTROL), group 2 received dexamethasone (DEXA), group 3 received DEXA and MegaSporeBiotic (MSB), group 4 received DEXA and metformin (MET), and group 5 received DEXA, MSB, and MET. On the last day of the experiment, blood samples and liver tissue samples for histopathological examination were collected. We determined serum glucose, total cholesterol, triglycerides, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), catalase, total antioxidant capacity (TAC), and metformin concentration. DEXA administration caused hyperglycemia and hyperlipidemia, increased inflammation cytokines, and decreased antioxidant markers. Treatment with MSB reduced total cholesterol, suggesting that the administration of Bacillus spores-based probiotics to DEXA-treated rats could ameliorate metabolic parameters.

Keywords: Bacillus spores; dexamethasone; dyslipidemia; hyperglycemia; inflammation; oxidative stress.

Figure 1

Serum glucose, total cholesterol, and triglycerides concentration. a: p < 0.05 compared to the CONTROL group; b: p < 0.05 compared to the DEXA group; c: p < 0.05 compared to the DEXA + MET group. Abbreviations: DEXA, dexamethasone; MSB, MegaSporeBiotic; MET, metformin. The bars represent mean values with a standard deviation.

Figure 2

Serum TNF-α, IL-6, and IL-10 levels. a: p < 0.05 compared to the CONTROL group; b: p < 0.05 compared to the DEXA group; c: p < 0.05 compared to the DEXA + MET group; d: p < 0.05 compared to the DEXA + MSB group. Abbreviations: TNF-α, tumor necrosis factor alpha; IL, interleukin; DEXA, dexamethasone; MSB, MegaSporeBiotic; MET, metformin. The bars represent mean values with a standard deviation.

Figure 3

TAC and catalase levels. a: p < 0.05 compared to the CONTROL group; Abbreviations: TAC, total antioxidant capacity; DEXA, dexamethasone; MSB, MegaSporeBiotic; MET, metformin. The bars represent mean values with a standard deviation.

Figure 4

Serum metformin levels. Abbreviations: DEXA, dexamethasone; MSB, MegaSporeBiotic; MET, metformin. The bars represent mean values with a standard deviation.

Figure 5

Photomicrographs of liver sections stained by H&E. (A): CONTROL group; ((A1), 20× and ((A2), 40×). (B): DEXA-treated rat group; ((B1), 20×); and ((B2), 40×). Alterations of hepatocytes structure and hepatic lobule architecture; enlarged, ballooned cells, with intracytoplasmic small lipid droplets in the perinuclear area(); large lipid droplets within the hepatocytes (); degenerated eosinophilic hepatocytes with pyknotic and hyperchromatic nuclei (); loss of cellular borders; vascular congestion in the central vein (); moderately dilated sinusoids with mild inflammatory infiltrate (polymorphonuclears neutrophils) within the sinusoids (). (C): DEXA + MSB treated rat group; ((C1), 20×) and ((C2), 40×). Partial reduction in lipid accumulation with small perinuclear lipid droplets within the hepatocytes (); moderate improvement in hepatocytes structure; mild central vein ectasia (); sinusoidal stasis and dilatation with few inflammatory cells (). (D): DEXA + MET-treated rat group; ((D1), 20×); and ((D2), 40×). Important restoration of the hepatic architecture and hepatocyte structure, with a significant reduction of intra-hepatocyte lipid content (); congestion within the portal vessels () and sinusoids (); mild central vein congestion and stasis (). (E): DEXA + MSB + MET-treated rat group; ((E1), 20×); and ((E2), 40×). Poor improvement in hepatic lobular architecture and hepatocyte structure with still disorganized cords of cells and high intracellular lipid accumulation (intra-hepatocyte small () and large lipid droplets) (); central vein congestion with intraluminal lymphocytes; (); moderate inflammatory infiltrate within the dilated sinusoids (). Abbreviations: H&E, hematoxylin, and eosin.

Figure 6

Experimental study design. Abbreviations: DEXA, dexamethasone; MSB, MegaSporeBiotic; MET, metformin; CMC, carboxymethylcellulose.