Table 2.

Summary of studies evaluating the effect of exercise training on BDNF levels and related metabolic indicators in patients with type 2 diabetes (animal studies)

Author-Date/PEDro Quality	Animals	Experimental Group (Independent Variable)	Control Group	Dependent Variable	Results
Eslami et al. (2016)/8 [63]	28 male Wistar rats, 10 months old. Diabetes Induction by intraperitoneal injection of streptozotocin. Groups: Healthy-Training, Diabetes-Training, Healthy-Inactive, and Diabetes-Inactive.	Treadmill running with moderate-intensity (50% -55% VO2max), 6 weeks, 5 session per week, 30 min per session, speed of 10 m in the minute of 24, for 10 min at speeds of 18–17 m per minute.	water and food feeding without training	BDNF Glucose	Significant compensation of BDNF reduction-induced by diabetes mellitus in the Diabetic-Training Group compared to Diabetic-Control Group at the sensory and motor roots of the lumbar nerves (absolute values were still lower than in the Healthy-Control Group). Significant reduction of glucose in the Diabetic-Training Group compared to Diabetic-Control Group.
Salehi et al. (2010)/8 [67]	48 male Wistar rats, 12-week-old. Diabetes Induction by intraperitoneal injection of streptozotocin. Groups: Healthy-Training, Diabetes-Training, Healthy-Inactive, and Diabetes-Inactive.	Swimming, 8 weeks, 6 Session per week, one hour per session.	Keeping in the lab and in the same conditions of animals of the training group, without swimming.	BDNF	Increased BDNF mRNA and protein gene expression in response to diabetes induction. Significant decrease in BDNF gene content and expression in diabetic rats in adaptation to training compared to the control group.
Kim et al. (2015)/7 [65]	18 Male Rats, Genetic Model of Type 2 Diabetes, 6 weeks. Groups: Active and inactive obese male rats, inactive lean male rats.	Progressive resistance training using a ladder and a weight attached to the tail of the rat, 8 weeks, 3 days per week (rats should reach the top of the ladder at 50% of their body weight and rest after 2 min, increasing by 20 g each time, this process repeated 10 times).	Without training	BDNF Glucose	Significant decrease in BDNF levels in the active obese group compared to the inactive obese group. Significant decrease in glucose level of active obese group compared to inactive obese group.
Stranahan et al. (2009)/6 [69]	Two groups, 24 male mice (one month old), ethnic background C57Bl/6, db/db mutant, and wild type. Groups: Training-Caloric restriction, Training-fed ad libitum, Inactive-Caloric restriction, Inactive-fed ad libitum (in mutated and wild-type groups)	Nutrition restriction: 60% of fed animals and once daily, The daily record of mice’s activities with software. The daily record of exercise activity (number of pedaling per day) on a wheel running with the software. 12 weeks.	Keeping in cage without wheel running	BDNF Glucose Insulin	Significant increase in BDNF levels with caloric restriction, training, or their combination in the db/db group, the elevation was higher in the wild group. Significant reduction in glucose between groups with combined running and caloric restriction. Significant decrease in insulin in the inactive-caloric restriction group.
Rashidi Molaei, Kazemi, & Rahmati (2015)/6 [66]	16 male Wistar rats (two weeks old). Diabetes induction by streptozotocin injection. Groups: diabetes-control, diabetes-training, healthy-control, and healthy-training.	Endurance training, 6 weeks, Moderate intensity, (speed of 10 m/min at first week, 17–18 m/min for 30 min).	Without training	BDNF Glucose	Significant decrease in BDNF expression and blood glucose level in the diabetes-training group
Hajizadeh Moghaddam et al. (2012)/6 [64]	42 male rats (eight weeks old). Diabetes induction by alloxan monohydrate injection. Groups: control, training, diabetes-training, diabetes-control, diabetes-alum, diabetes-alum-training.	6 weeks of voluntary wheel running.	Without training with alum feeding	BDNF	Increased hippocampal BDNF in voluntary wheel running with alum paradoxoxum.
Salehi & Hoseini (2017)/6 [68]	48 male rats, diabetes induction by streptozotocin. Groups: diabetic rats sacrificed at first-week, diabetic rats sacrificed at last week, diabetic rats doing moderate-intensity endurance training, diabetic rats doing High-intensity endurance training, healthy rats sacrificed at first week, healthy rats sacrificed at last week.	Eight weeks treadmill running, three sessions per week, 60 min per session, at speed of 10–17 m/min and 17–28 m/min.	Without training	BDNF Insulin	8 weeks of moderate to high intensity endurance training significantly increased BDNF levels. But did not affect insulin levels in diabetic rats.