Correction: Shawky et al. The Biological Impacts of Sitagliptin on the Pancreas of a Rat Model of Type 2 Diabetes Mellitus: Drug Interactions with Metformin. Biology 2020, 9, 6.

In the original publication [...].

Targeting NF-κB/COX-2 signaling by soyasaponin I alleviates diclofenac-induced gastric ulceration in male albino rats.

Gastric ulceration is a prevalent worldwide clinical presentation due to altered gastric defense mechanisms. Nonsteroidal anti-inflammatory drugs are one of the common causes of gastric ulcers mediated by the release of inflammatory mediators. The study aimed to investigate the potential protective effect of soyasaponin I (soya) against diclofenac (DIC)-induced gastric ulcer in rats and to highlight the underlying mechanisms. The experiment was conducted on 40 male Wistar albino rats, equally distributed into five groups: control, DIC-induced ulcer (9 mg/kg/d, orally, twice daily for 3 days), ulcer/soya-, ulcer/ranitidine-, and ulcer/soya/selective nuclear factor kappa B inhibitor (JSH-23)-treated groups. The doses of soya, ranitidine, and JSH were 20, 25, and 5 mg/kg/d, respectively, given orally. Gastric specimens were prepared for gene and histological study and for biochemical analysis of gastric prostaglandin E2 (PGE2), oxidative markers, and inflammatory cytokines. The gastric samples were formalin-fixed, paraffin-embedded, and subjected to hematoxylin and eosin (H&E), PAS staining, and immunohistochemical assay for identification of nuclear factor kappa B (NF-κB), cyclooxygenase-2 (COX-2), and proliferation marker (Ki67) expressions. The findings revealed decreased gastric PGE2 and altered inflammatory and oxidative markers in the ulcer model group. The H&E staining showed mucosal injury characterized by mucosal surface defects and inflammatory cell infiltrations. The polymerase chain reaction (PCR) and immunohistochemistry demonstrated an upregulation of NF-κB and COX-2 expression at gene/protein levels; meanwhile, Ki67 downregulation. The soya-treated group showed maintained biochemical, histological, and PCR findings comparable to the ranitidine-treated group. The JSH-23-treated group still showed partial gastric protection with biochemical and immunohistochemical changes. Soyasaponin I ameliorated DIC-induced gastric ulcers by targeting the COX-2 activity through modulation of NF-κB signaling.

The Biological Impacts of Sitagliptin on the Pancreas of a Rat Model of Type 2 Diabetes Mellitus: Drug Interactions with Metformin.

Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, is a beneficial class of antidiabetic drugs. However, a major debate about the risk of developing pancreatitis is still existing. The aim of the work was to study the histological and immunohistochemical effects of sitagliptin on both endocrine and exocrine pancreases in a rat model of type 2 diabetes mellitus and to correlate these effects with the biochemical findings. Moreover, a possible synergistic effect of sitagliptin, in combination with metformin, was also evaluated. Fifty adult male rats were used and assigned into five equal groups. Group 1 served as control. Group 2 comprised of untreated diabetic rats. Group 3 diabetic rats received sitagliptin. Group 4 diabetic rats received metformin. Group 5 diabetic rats received both combined. Treatments were given for 4 weeks after the induction of diabetes. Blood samples were collected for biochemical assay before the sacrification of rats. Pancreases were removed, weighed, and were processed for histological and immunohistochemical examination. In the untreated diabetic group, the islets appeared shrunken with disturbed architecture and abnormal immunohistochemical reactions for insulin, caspase-3, and inducible nitric oxide synthase (iNOS). The biochemical findings were also disturbed. Morphometrically, there was a significant decrease in the islet size and islet number. Treatment with sitagliptin, metformin, and their combination showed an improvement, with the best response in the combined approach. No evidence of pancreatic injury was identified in the sitagliptin-treated groups. In conclusion, sitagliptin had a cytoprotective effect on beta-cell damage. Furthermore, the data didn't indicate any detrimental effects of sitagliptin on the exocrine pancreas.

Stem cells and metformin synergistically promote healing in experimentally induced cutaneous wound injury in diabetic rats.

INTRODUCTION: Diabetes mellitus (DM) is a serious, chronic metabolic disorder commonly complicated by diabetic foot ulcers with delayed healing. Metformin was found to have a wound healing effect through several mechanisms. The current study investigated the effect of both bone marrow-derived mesenchymal stem cells (BM-MSCs) and metformin, considered alone or combined, on the healing of an experimentally induced cutaneous wound injury in streptozotocin-induced diabetic rats. MATERIAL AND METHODS: Forty adult male albino rats were used. Diabetes was induced by single intravenous (IV) injection of streptozotocin (STZ). Next, two circular full thickness skin wounds were created on the back of the animals, then randomly assigned into 4 groups, ten rats each. BM-MSCs were isolated from albino rats, 8 weeks of age and labeled by PKH26 before intradermal injection into rats of Group III and IV. Groups I (diabetic positive control), II (metformin-treated, 250 mg/kg/d), III (treated with 2×106 BM-MSCs), and IV (wounded rats treated both with metformin and BM-MSCs cells). Healing was assessed 3, 7, 14, and 21 days post wound induction through frequent measuring of wound diameters. Skin biopsies were obtained at the end of the experiment. RESULTS: Gross evaluation of the physical healing of the wounds was done. Skin biopsies from the wound areas were processed for hematoxylin and eosin (H&E), Masson's trichrome staining and immunohistochemical staining for CD31. The results showed better wound healing in the combined therapy group (IV) as compared to monotherapy groups. CONCLUSIONS: Although both metformin and BM-MSCs were effective in the healing of experimentally induced skin wounds in diabetic rats, the combination of both agents appears to be a better synergistic option for the treatment of diabetic wound injuries.