Probiotic (protexin) modulates glucose level in sucrose-induced hyperglycaemia in Harwich strain Drosophila melanogaster
Authors: Abdulazeez Jimoh , Zainab Muhammad , Muhammad Aliyu 
Published: July 2022

Abstract
Background
Probiotics are beneficial microorganisms that alter microbial flora to promote human and animal health by ameliorating the physiological and psychological hitches and distress. The aim of the study was to investigate the protective effect of probiotic (protexin) in sucrose induced hyperglycaemia in Harwich strain Drosophila melanogaster.

Methods
For lethal concentration, different concentrations of probiotic were fed on fresh breaded D. melanogaster for two weeks in two phases. The concentrations varied from 10 to 1000 mg. For increment in haemolymph glucose level, Insta-larva of 540 D melanogaster was divided into six groups of thirty larva (n = 30) each in triplicate. Baseline glucose level was determined by administering group normal diet, while group 2–6 were fed with a normal diet containing 30% sucrose. For body weight, Eppendorf microtubes were weighed and anaesthetised flies were transferred into the tubes which were, re-weigh to get the actual weight of the flies before and after sucrose intake. Treatment supplement was introduced after flies emerged to be three days old. Group I: (Normal Control) received a normal cornmeal diet 30 g. Group II: (positive control) received normal diet + 30% sucrose only. Group III; received 10 mg of metformin/30 g diet. Group IV received 250 mg of probiotic/30 g of normal diet. Group V received 500 mg of probiotic/30 g normal diet. Group VI received 1000 mg of probiotic/30 g normal diet. All treatments lasted for 7 days. At the end of the treatment period, flies were immobilized and anaesthetised in ice and homogenised vigorously in 0.1 M phosphate buffer, pH 7.4. Eppendorf microtubes were weighed and anesthetized flies were transferred into them, and re-weighed with appropriate micro-litre of phosphate buffered saline (PBS) added and the flies were squashed to get the supernatant. The resulting homogenates were centrifuged at 10,000×g, 4 °C for 10 min. The supernatant was separated from the pellets into labelled tubes and used for the various biochemical assays. Data were expressed as mean ± standard error of mean (SEM) and subjected one-way analysis of variance (ANOVA), followed by Tukey post-hoc test for multiple comparisons between groups. Statistical package Graph Pad Prism version 8.1 was used for statistical analysis and values of p ˂ 0.05 were considered significant. Lethal concentration, logic probit test software was used.

Results
The dosage of probiotic ranging from 10 to 1000 mg were not toxic to the fruit-fly. The LC50 of protexin after seven days was found to be greater than 1000 mg. Significantly (p < 0.05) decreased in hemolymph glucose concentration was recorded for the base-line (phase one) in the normal control group, compared to diabetic-induced groups. There was a significant (p < 0.05) decline in body weight and blood glucose level in all the treatment groups, when compared to the diabetic untreated group.

Conclusions
Administration of sucrose diet increased the blood glucose level and body weight in diabetic D. melanogaster flies, mitigated by administration of probiotics (protexins).