Induction of diabetes in rats

Diabetes was induced in overnight fasted Sprague Dawley rats by injecting alloxan (120 mg/kg/BW) dissolved in normal saline, through the subcutaneous route. Glucose solution (20% (w/v)) was also given to these rats to prevent fatal post-alloxan hypoglycemia. After 48 h of alloxan administration, the rats with fasting blood glucose levels>250 mg/dl were considered diabetic and were included in the study [18, 30].

The animals were randomly divided into six groups (7 rats each):

► Group 1 (NC): Normal rats fed with control bread.

► Group 2 (DC): Diabetic rats fed with control bread.

► Group 3 (OPE_1): Diabetic rats fed with bread supplemented with OPE (1%).

► Group 4 (OPE_3): Diabetic rats fed with bread supplemented with OPE (3%).

► Group 5 (OP_5): Diabetic rats fed with bread supplemented with onion powder (5%).

► Group 6 (OP_7): Diabetic rats fed with bread supplemented with onion powder (7%).

Before starting the trial, fasting blood glucose level (mg/dl) and body weight (g) were determined using a glucometer [31] and weighing scale, respectively. The modified diet was then given to the rats for 8 weeks. During the study, physical parameters such as water and bread consumption were measured daily (Appendix Table 4) while blood glucose was determined fortnightly. At the end of the trial, the rats fasted for 12 h and the final measurement of blood glucose level and body weight was taken [32]. All rats were anesthetized and sacrificed as per ethical committee guidelines and at 4 °C, the kidney and liver tissues were excised. Ice-cold saline was used to wash the isolated tissues that were later dipped in liquid nitrogen and instantly stored at −80 °C until further analysis [33].