High-Intensity Interval Training-Induced Hippocampal Molecular Changes Associated with Improvement in Anxiety-like Behavior but Not Cognitive Function in Rats with Type 2 Diabetes

The effect of 12 weeks of aerobic exercise training with or without saffron supplementation on diabetes-specific markers and inflammation in women with type 2 diabetes: A randomized double-blind placebo-controlled trial

This study was conducted to investigate the effects of 12 weeks of aerobic exercise (AT) and saffron supplementation on hemostasis, inflammatory markers, and insulin resistance in obese women diagnosed with type 2 diabetes (T2D). A total of 44 women with T2D (mean age: 54.12 ± 5.63 years, mean BMI: 31.15 ± 1.50 kg/m2, HbA1c: 85 ± 4.2 mmol/mol) were included in a randomized, double-blind, placebo-controlled study. We were randomly assigned to one of four groups (n = 11 per group): saffron + training (ST), placebo + training (PT), saffron supplement (SS), and placebo (P). The ST and PT groups completed 12 weeks of AT (three sessions per week of mild to moderate intensity). The ST and SS groups were administered a daily dose of 200 mg of saffron powder for 12 weeks. Fasting blood samples were collected 48 h before the first AT session and/or nutritional supplementation and 48 h after the last AT session and/or nutritional supplementation. Post-evaluation, homeostatic model assessment of insulin resistance value (HOMA-IR, p < 0.001) and serum levels of glucose (p < 0.001), fibrinogen (FIB, p < 0.001), homocysteine (HCY, p < 0.001), interleukin-6 (IL-6, p < 0.001), and tumor necrosis factor α (TNFα, p < 0.001) showed significant reduction in the ST, PT, and SS groups compared to the P group (p < 0.05). In particular, the ST group showed a more significant reduction in all variables compared to the PT and SS groups (p < 0.05). Our results suggest that a 12-week intervention with AT and saffron supplementation can independently improve markers related to hemostasis, inflammation, and insulin resistance. However, their combination showed the greatest effectiveness on the above markers.

High-Intensity Interval Training Ameliorates Tramadol-Induced Nephrotoxicity and Oxidative Stress in Experimental Rats

INTRODUCTION

Tramadol (TRA) is an opioid analgesic widely prescribed for moderate-to-severe pain; however, its abuse and chronic use have been associated with kidney damage. Considering the protective role of exercise training in reducing organ damage, this study aimed to assess the influence of high-intensity interval training (HIIT) on a male rat's kidney following chronic TRA administration.

METHODS

In this experimental study, 30 male Wistar rats were assigned to the following groups: control (CON; animals received normal saline five days a week in the first month and three days a week in the second month), exercise (EXE; animals conducted HIIT training according to exercise protocol five days a week for two months), TRA (animals received TRA 50 mg/kg (i.p.) as described for the CON group), EXE-TRA (animals received TRA and conducted exercise protocol), and EXE-SL (animals received normal saline and conducted exercise protocol). Then, serum IL-6 and IL-10 levels, tissue malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione peroxidase (GPx), superoxide dismutase (SOD), and levels of albumin, urea, and creatinine (CR), along with pathological changes in the kidney, were measured. A p-value of <0.05 was considered significant using GraphPad Prism v.9 (GraphPad Software, La Jolla, California, USA).

RESULTS

The inflammatory cytokines IL-6 and IL-10 were significantly increased in the EXE and EXE-TRA groups compared to the TRA group. Chronic administration of TRA in the TRA group decreased antioxidant indicators TAC, GPx, and SOD in kidney tissue while increasing oxidative stress MDA compared to the CON group (p<0.05). In contrast, the EXE-TRA group showed higher levels of TAC, GPx, and SOD, while MDA decreased compared to the TRA group. Additionally, serum levels of urea and CR were increased in the TRA group compared to the CON group, whereas these levels were decreased in the EXE-TRA group compared to the TRA group. The inflammatory effect of HIIT training, due to severe hyperemia and mild inflammatory cell infiltration, was seen in all EXE groups. Pathological findings confirmed TRA-induced kidney damage through moderate hyaline cast presence and severe apoptosis in the TRA group. Other findings were in line with the above results.

CONCLUSION

These findings confirm the nephrotoxicity of chronic use of TRA through biochemical and oxidative markers and pathological outcomes. In addition, the result suggests that HIIT has the potential to mitigate the detrimental effects of TRA through reversing biochemical and oxidative markers, including TRA-induced apoptosis. Consequently, considering its restorative properties, HIIT could be explored as a prospective nephroprotective approach for long-term TRA treatment.

High-intensity interval training mitigates the progression of periodontitis and improves behavioural aspects in rats

AIM

To investigate the effects of high-intensity interval training (HIIT) on periodontitis (PD) progression and behavioural outcomes.

MATERIALS AND METHODS

Forty-eight Wistar rats were divided into four groups: non-trained (NT); non-trained with PD; HIIT with PD; and HIIT. The HIIT protocol, involving daily treadmill sessions, spanned 8 weeks, with PD induced by ligature after the 6th week. Behavioural tests were conducted to assess anxiety and memory. Post euthanasia, we evaluated the systemic inflammatory profile and oxidative stress markers in the hippocampus and amygdala. A morphological evaluation and elemental composition analysis of the mandibular alveolar bone were performed.

RESULTS

PD exacerbated alveolar bone level, bone surface damage and alterations in calcium and phosphorus percentages on the bone surface (p < .05), while HIIT attenuated these changes (p < .05). HIIT improved systemic inflammatory markers altered by PD (tumour necrosis factor [TNF]-α, interleukin [IL]-10, TNF-α/IL-10 and IL-1β/IL-10 ratios, p < .05). PD animals exhibited lower total antioxidant capacity and levels of thiobarbituric acid reactive substances in the amygdala and hippocampus, respectively (p < .05). HIIT maintained these parameters at levels similar to those in NT animals. HIIT improved anxiety and memory outcomes altered by PD (p < .05).

CONCLUSIONS

HIIT attenuates systemic inflammation, anxiety and memory outcomes promoted by PD.

Changes in the hippocampal level of tau but not beta-amyloid may mediate anxiety-like behavior improvement ensuing from exercise in diabetic female rats

BACKGROUND

In the present study, we investigated the effect of high-intensity interval training (HIIT) on cognitive behaviors in female rats with a high-fat diet + streptozotocin (STZ)-induced type 2 diabetes.

METHODS

Twenty-four female rats were divided into four groups randomly (n = 6): control (C), control + exercise (Co + EX), diabetes mellitus (type 2) (T2D), and diabetes mellitus + exercise (T2D + EX). Diabetes was induced by a two-month high-fat diet and a single dose of STZ (35 mg/kg) in the T2D and T2D + EX groups. The Co + EX and T2D + EX groups performed HIIT for eight weeks (five sessions per week, running on a treadmill at 80-100% of VMax, 4-10 intervals). Elevated plus maze (EPM) and open field test (OFT) were used for assessing anxiety-like behaviors, and passive avoidance test (PAT) and Morris water maze (MWM) were applied for evaluating learning and memory. The hippocampal levels of beta-amyloid (Aβ) and Tau were also assessed using Western blot.

RESULTS

An increase in fasting blood glucose (FBG), hippocampal level of Tau, and a decrease in the percentage of open arm time (%OAT) as an index of anxiety-like behavior were seen in the female diabetic rats which could be reversed by HIIT. In addition, T2D led to a significant decrease in rearing and grooming in the OFT. No significant difference among groups was seen for the latency time in the PAT and learning and memory in the MWM.

CONCLUSIONS

HIIT could improve anxiety-like behavior at least in part through changes in hippocampal levels of Tau.

Liraglutide versus pramlintide in protecting against cognitive function impairment through affecting PI3K/AKT/GSK-3β/TTBK1 pathway and decreasing Tau hyperphosphorylation in high-fat diet- streptozocin rat model

The American Diabetes Association guidelines (2021) confirmed the importance of raising public awareness of diabetes-induced cognitive impairment, highlighting the links between poor glycemic control and cognitive impairment. The characteristic brain lesions of cognitive dysfunction are neurofibrillary tangles (NFT) and senile plaques formed of amyloid-β deposition, glycogen synthase kinase 3 beta (GSK3β), and highly homologous kinase tau tubulin kinase 1 (TTBK1) can phosphorylate Tau proteins at different sites, overexpression of these enzymes produces extensive phosphorylation of Tau proteins making them insoluble and enhance NFT formation, which impairs cognitive functions. The current study aimed to investigate the potential contribution of liraglutide and pramlintide in the prevention of diabetes-induced cognitive dysfunction and their effect on the PI3K/AKT/GSK-3β/TTBK1 pathway in type 2 diabetic (T2D) rat model. T2D was induced by administration of a high-fat diet for 10 weeks, then injection of a single dose of streptozotocin (STZ); treatment was started with either pramlintide (200 μg/kg/day sc) or liraglutide (0.6 mg/kg/day sc) for 6 weeks in addition to the HFD. At the end of the study, cognitive functions were assessed by novel object recognition and T-maze tests. Then, rats were sacrificed for biochemical and histological assessment of the hippocampal tissue. Both pramlintide and liraglutide treatment revealed equally adequate control of diabetes, prevented the decline in memory function, and increased PI3K/AKT expression while decreasing GSK-3β/TTBK1 expression; however, liraglutide significantly decreased the number of Tau positive cells better than pramlintide did. This study confirmed that pramlintide and liraglutide are promising antidiabetic medications that could prevent associated cognitive disorders in different mechanisms.

Exercise training improves diabetic renal injury by reducing fetuin-A, oxidative stress and inflammation in type 2 diabetic rats

Background

Diabetic kidney disease (DKD) stands as a primary contributor to end-stage renal disease, associated with heightened mortality in cardiovascular diseases. This study aimed to explore the impact of an eight-week high-intensity interval training (HIIT) on renal injury in diabetic rats.

Methods

Twenty-eight male Wistar rats were randomly allocated into four groups: healthy control (CTL), diabetic control (DC), exercise (EX), and diabetes-exercise (D + EX). Induction of diabetes in the DC and D + EX groups occurred through a two-month high-fat diet followed by a single dose of 35 mg/kg streptozotocin (STZ). Rats in the EX and D + EX groups underwent 4-10 intervals of HIIT (80-100% Vmax) over 8 weeks. Subsequently, pathological and biochemical parameters were assessed in the serum and kidney tissue of the experimental groups.

Results

In the DC group, diabetes led to elevated kidney damage, glomerulosclerosis, fasting blood glucose (FBG), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) index, animal weight, kidney dysfunction, albuminuria, and glomerular filtration rate. Additionally, serum and kidney levels of fetuin-A increased, along with kidney levels of KIM-1. Mechanistically, diabetes induction resulted in kidney inflammation by elevating levels of tumor necrosis factor-alpha (TNF-α), transforming growth factor beta (TGF-β), and interleukin 6 (IL-6), while reducing IL-10 levels and increasing the IL-6/IL-10 ratio. Furthermore, diabetes triggered renal oxidative stress, evidenced by increased Malondialdehyde (MDA) levels and decreased levels of glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD). HIIT mitigated the adverse effects of diabetes in the D + EX group compared to the DC group.

Conclusion

Our findings suggest that HIIT ameliorates type 2 diabetes (T2D)-induced kidney damage by mitigating inflammation, lowering serum levels of fetuin-A, and bolstering antioxidant defenses. This study highlights the potential of HIIT as a time-efficient intervention for diabetic nephropathy.

ATP releasing channels and the ameliorative effects of high intensity interval training on diabetic heart: a multifaceted analysis

Type 2 diabetes (T2D) can cause severe cardiac complications at functional, histologic and molecular levels. These pathological complications could be mediated by ATP-releasing channels such as Panx1 and ATP receptors, in particular P2X7. The aim of our study was to investigate the effect of high-intensity interval training (HIIT) on T2D-induced cardiac complications at the functional, histopathological and molecular levels, with a particular focus on ATP-releasing channels. 48 male Wistar rats at the age of 8 weeks were randomly allocated into four groups: control (Con), Diabetes (T2D), Training (TR), and Diabetes + Training (T2D + TR). T2D was induced by a high-fat diet plus a low dose (35 mg/kg) of STZ administration. Rats in the TR and T2D + TR groups underwent an 8-weeks training program involving intervals ranging from 80 to 100% of their maximum running speed (Vmax), with 4-10 intervals per session. Protein expression of Interleukin 1β (IL1β), Interleukin 10 (IL-10), Pannexin 1 (Panx1), P2X7R (purinergic P2X receptor 7), NLRP1 (NLR Family Pyrin Domain Containing 1), BAX, and Bcl2 were measured in the heart tissue. Additionally, we assessed heart function, histopathological changes, as well as insulin resistance using the homeostasis model assessment of insulin resistance (HOMA-IR). In contrast to the T2D group, HIIT led to increased protein expression of Bcl2 and IL-10 in the heart. It also resulted in improvements in systolic and diastolic blood pressures, heart rate, ± dp/dt (maximum and minimum changes in left ventricular pressure), while reducing protein expression of IL-1β, Panx1, P2X7R, NLRP1, and BAX levels in the heart. Furthermore, left ventricular diastolic pressure (LVDP) was reduced (P ≤ 0.05). Moreover, heart lesion scores increased with T2D but decreased with HIIT, along with a reduction in fibrosis percentage (P ≤ 0.05). The results of this study suggest that the cardioprotective effects of HIIT on the diabetic heart may be mediated by the modulation of ATP-releasing channels. This modulation may lead to a reduction in inflammation and apoptosis, improve cardiac function, and attenuate cardiac injury and fibrosis.

Cognitive Fitness: Harnessing the Strength of Exerkines for Aging and Metabolic Challenges

Addressing cognitive impairment (CI) represents a significant global challenge in health and social care. Evidence suggests that aging and metabolic disorders increase the risk of CI, yet promisingly, physical exercise has been identified as a potential ameliorative factor. Specifically, there is a growing understanding that exercise-induced cognitive improvement may be mediated by molecules known as exerkines. This review delves into the potential impact of aging and metabolic disorders on CI, elucidating the mechanisms through which various exerkines may bolster cognitive function in this context. Additionally, the discussion extends to the role of exerkines in facilitating stem cell mobilization, offering a potential avenue for improving cognitive impairment.

Lactate-induced autophagy activation: unraveling the therapeutic impact of high-intensity interval training on insulin resistance in type 2 diabetic rats

Impaired autophagy is a hallmark of diabetes. The current study proposed to investigate if high intensity interval training (HIIT) induced lactate accumulation could stimulate autophagy in type 2 diabetic male rats. 28 male Wistar rats were randomly assigned into four groups: Healthy Control (CO), Diabetes Control (T2D), Exercise (EX), and Diabetes + Exercise (T2D + EX). Diabetes was induced by feeding high-fat diet and administrating single dose of streptozotocin (35 mg/kg). After becoming diabetic, the animals in the exercise groups (EX and T2D + EX) performed an eight-week HIIT (4-10 interval, 80-100% Vmax, 5 days per week). Serum levels of lactate, glucose and insulin as well as the levels of lactate, pyruvate, lactate transporter monocarboxylate transporter 1 (MCT1), phosphorylated mitogen-activated protein kinases (p-MAP 1 and 2), phosphorylated extracellular signal-regulated protein kinases 1 and 2 (p-ERK 1 and 2), mammalian target of rapamycin (p-mTOR), ribosomal protein S6 kinase beta-1 (p-70S6k), p90 ribosomal S6 kinases (p-90RSK), autophagy related 7 (ATG7), Beclin-1, microtubule-associated protein 1A/1B, and 2A/2B -light chain 3 levels (LC3-I), (LC3- II), (LC3I/LC3II) in soleus muscle were measured. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and serum glucose was lower in T2D + EX compared to T2D group (P < 0.0001). While serum and soleus muscle levels of lactate was not different between T2D and T2D + Ex, the levels of Pyruvate (P < 0.01), MCT1, p-ERK1/2, p-mTOR, p70S6k, P-90RSK, ATG7, LC3-II, and LC3-II/LC3I ratios were higher in T2D + EX compared to T2D group (P < 0.0001). We concluded that eight weeks of high-intensity interval training could activated ERK/P90SRK while inhibiting mTOR/P70S6K signaling pathway in lactate dependent manner. It means increased autophagy which resulted in improve insulin resistance (IR) and reduce blood glucose.

High Intensity Interval Training can Ameliorate Hypothalamic Appetite Regulation in Male Rats with Type 2 Diabetes: The Role of Leptin

Disruption of leptin (LEP) signaling in the hypothalamus caused by type 2 diabetes (T2D) can impair appetite regulation. The aim of this study was to investigate whether the improvement in appetite regulation induced by high-intensity interval training (HIIT) in rats with T2D can be mediated by LEP signaling. In this study, 20 male Wister rats were randomly assigned to one of four groups: CO (non-type 2 diabetes control), T2D (type 2 diabetes), EX (non-type 2 diabetes exercise), and T2D + EX (type 2 diabetes + exercise).To induce T2D, a combination of a high-fat diet for 2 months and a single dose of streptozotocin (35 mg/kg) was administered. Rats in the EX and T2D + EX groups performed 4-10 intervals of treadmill running at 80-100% of their maximum velocity (Vmax). Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), serum levels of insulin (INS) and LEP (LEPS) as well as hypothalamic expression of LEP receptors (LEP-R), Janus kinase 2 (JAK-2), signal transducer and activator of transcription 3 (STAT-3), neuropeptide Y (NPY), agouti-related protein (AGRP), pro-opiomelanocortin cocaine (POMC), amphetamine-related transcript (CART), suppressor of cytokine signaling (SOCS3), forkhead box protein O1 (FOXO1) were assessed. ANOVA and Tukey post hoc tests were used to compare the results between the groups. The levels of LEPS and INS, as well as the levels of LEP-R, JAK-2, STAT-3, POMC, and CART in the hypothalamus were found to be higher in the T2D + EX group compared to the T2D group. On the other hand, the levels of HOMA-IR, NPY, AGRP, SOCS3, and FOXO1 were lower in the T2D + EX group compared to the T2D group (P < 0.0001). The findings of this study suggest that HIIT may improve appetite regulation in rats with T2D, and LEP signaling may play a crucial role in this improvement. Graphical abstract (leptin signaling in the hypothalamus), Leptin (LEP), Leptin receptor (LEP-R), Janus kinase 2 (JAK2), Signal transducer and activator of transcription 3 (STAT3), expressing Neuropeptide Y (NPY), Agouti-related protein (AGRP), anorexigenic neurons (expressing pro-opiomelanocortin cocaine (POMC), Amphetamine-related transcript (CART), suppressor of cytokine signaling (SOCS3), forkhead box protein O1 (FOXO1).

Leptin Signaling Could Mediate Hippocampal Decumulation of Beta-Amyloid and Tau Induced by High-Intensity Interval Training in Rats with Type 2 Diabetes

Leptin (LEP) can cross the blood-brain barrier and facilitate cross-talk between the adipose tissue and central nerve system (CNS). This study aimed to investigate the effect of 8-week high-intensity interval training (HIIT) on the LEP signaling in the hippocampus of rats with type 2 diabetes. 20 rats were randomly divided into four groups: (i) control (Con), (ii) type 2 diabetes (T2D), (iii) exercise (EX), and (iv) type 2 diabetes + exercise (T2D + EX). The rats in the T2D and T2D + EX were fed a high-fat diet for two months, then a single dose of STZ (35 mg/kg) was injected to induce diabetes. The EX and T2D + EX groups performed 4-10 intervals of treadmill running at 80-100% of Vmax. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP receptors (LEP-R), Janus kinase 2 (JAK-2), signal transducer and activator of transcription 3 (STAT-3), activated protein kinase (AMP-K), proxy zoster receptor α (PGC-1α), beta-secretase 1 (BACE1), Beta-Amyloid (Aβ), Phosphoinositide 3-kinases (PI3K), protein kinase B (AKT), mammalian target of rapamycin (mTOR), Glycogen Synthase Kinase 3 Beta (GSK3β), and hyperphosphorylated tau proteins (TAU) were measured. One-way ONOVA and Tukey post-hoc tests were used to analyze the data. Serum and hippocampal levels of LEP as well as hippocampal levels of LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were increased while hippocampal levels of BACE1, GSK3B, TAU, and Aβ were decreased in T2D + EX compared with T2D group. Serum LEP and hippocampal levels of LEP, LEP-R, JAK-2, STAT-3, AMP-K, PGC1α, PI3K, AKT, and mTOR were decreased. Conversely hippocampal levels of BACE1, GSK3B, TAU, and Aβ were increased in T2D group compared with CON group. HIIT could improve LEP signaling in the hippocampus of rats with type 2 diabetes and decrease the accumulation of Tau and Aβ, which may reduce the risk of memory impairments.

Adiponectin receptor 1 could explain the sex differences in molecular basis of cognitive improvements induced by exercise training in type 2 diabetic rats

Adipokines dysregulation, the main reason for cognitive impairments (CI) induced by diabetes, shows a sex-dependent pattern inherently and in response to exercise. This study aimed to compare the attenuating effect of 8-week high intensity-interval training (HIIT) on type 2 diabetes (T2D)-induced CI between male and female rats with a special focus on adiponectin and leptin. 28 male & 28 female Wistar rats with an average age of 8 weeks were randomly assigned into four groups: control (Con), exercise (EX), Diabetes (T2D), and Type 2 diabetes + exercise (T2D + Ex). Rats in EX and T2D + EX groups performed HIIT for eight weeks (80-100% Vmax, 4-10 intervals). T2D was induced by 2 months of a high-fat diet and a single dose of STZ (35 mg/kg) administration. Leptin and adiponectin levels in serum were measured along with hippocampal expression of leptin and adiponectin receptors, AMP-activated protein kinase (AMPK), dephosphorylated glycogen synthase kinase-3 beta (Dep-GSK3β), Tau, and beta-amyloid (Aβ). Homeostasis model assessments (HOMAs) and quantitative insulin-sensitivity check index (QUICKI) indices were calculated. Our results showed that following T2D, serum levels of APN, and hippocampal levels of adiponectin receptor 1 (APNR1) were higher and HOMA-IR was lower in female than male rats (P < 0.05). However, after 8 weeks of HIIT, hippocampal levels of APNR1 and AMPK as well as QUICKI were lower and hippocampal levels of GSK, Tau, and Aβ were higher in females compared to male rats (P < 0.05). While the risk of CI following T2D was more in male than female rats HIIT showed a more ameliorating effect in male animals with APN1 as the main player.

High-Intensity Interval Training Ameliorates Molecular Changes in the Hippocampus of Male Rats with the Diabetic Brain: the Role of Adiponectin

Alzheimer's disease (AD) is closely related to type 2 diabetes (T2D). This study investigated the impact of high-intensity interval training (HIIT) on diabetes-induced disturbances in AD-related factors (including AMP-activated protein kinase (AMPK), glycogen synthase kinase-3β (GSK3β), and tau protein) in the hippocampus, with the main focus on adiponectin signaling.In total, 28 male Wistar rats at the age of 8 weeks were randomly assigned to four groups (n = 7 in each group): control (Con), type 2 diabetes (T2D), HIIT (Ex), and type 2 diabetes + HIIT (T2D + Ex). T2D was induced by a high-fat diet plus a single dose of streptozotocin (STZ). Rats in Ex and T2D + Ex groups performed 8 weeks of HIIT (running at 8-95% of V_max, 4-10 intervals). Insulin and adiponectin levels in serum and hippocampus were measured along with hippocampal expression of insulin and adiponectin receptors, phosphorylated AMPK, dephosphorylated GSK3β, and phosphorylated tau. Homeostasis model assessment for insulin resistance (HOMA-IR), homeostasis model assessment for insulin resistance beta (HOMA-β), and quantitative insulin sensitivity check index (QUICKI) were calculated to assess insulin resistance and sensitivity. T2D decreased insulin and adiponectin levels in serum and hippocampus, as well as the hippocampal levels of insulin and adiponectin receptors and AMPK, but increased GSK3β and tau in the hippocampus. HIIT reversed diabetes-induced impairments and consequently decreased tau accumulation in the hippocampus of diabetic rats. HOMA-IR, HOMA-β, and QUICKI were improved in Ex and T2D + Ex groups. Overall, our results confirmed that T2D has undesirable effects on the levels of some Alzheimer's-related factors in the hippocampus, and HIIT could ameliorate these impairments in the hippocampus.