Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model

Elizabeth Eepho Krukru; Bruno Chukwuemeka Chinko; Victor Datonye Dapper

doi:doi:10.11648/j.bs.20261201.12

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Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model

Elizabeth Eepho Krukru^*

, Bruno Chukwuemeka Chinko

, Victor Datonye Dapper

Published in Biomedical Sciences (Volume 12, Issue 1)

Received: 18 January 2026 Accepted: 2 February 2026 Published: 21 February 2026

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Abstract

Brain-derived neurotrophic factor (BDNF) is a critical regulator of neuronal survival, synaptic plasticity, and cognitive function, making it a key biomarker in understanding the neurobiological impact of opioid exposure. This study investigated the effects of opioids (codeine and tramadol) on brain-derived neurotrophic factor (BDNF) levels in male Wistar rats. A total of 75 male Wistar rats (120-140g) were used for the study in acute, sub-chronic and chronic phases, using 25 rats for each phase. In each phase, 25 male Wistar rats were divided into 5 groups of 5 animals each. Group 1 served as the control and received distilled water, groups 2 and 3 were treated with tramadol at 20 and 60 mg/kg, respectively, while groups 4 and 5 were supplemented with codeine at 10 and 30 mg/kg, respectively. Treatment by oral gavage lasted for 14, 28 and 56 days for the acute, sub-chronic and chronic studies, respectively. Serum and hippocampal BDNF assays were analysed following standard laboratory protocols. Results showed dose and time-dependent significant reductions (p < 0.05) in BDNF levels across all treatment groups compared to controls, with the most pronounced decreases observed in codeine 30mg/kg and tramadol 60mg/kg groups. These findings suggest that prolonged opioid exposure disrupts neurotrophic signalling, potentially contributing to neurodegenerative conditions.

Published in	Biomedical Sciences (Volume 12, Issue 1)
DOI	10.11648/j.bs.20261201.12
Page(s)	10-16
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2026. Published by Science Publishing Group

Keywords

Brain-derived Neurotrophic Factor (BDNF), Opioids, Neurodegenerative Conditions

References

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APA Style

Krukru, E. E., Chinko, B. C., Dapper, V. D. (2026). Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model. Biomedical Sciences, 12(1), 10-16. https://doi.org/10.11648/j.bs.20261201.12

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ACS Style

Krukru, E. E.; Chinko, B. C.; Dapper, V. D. Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model. Biomed. Sci. 2026, 12(1), 10-16. doi: 10.11648/j.bs.20261201.12

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AMA Style

Krukru EE, Chinko BC, Dapper VD. Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model. Biomed Sci. 2026;12(1):10-16. doi: 10.11648/j.bs.20261201.12

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@article{10.11648/j.bs.20261201.12,
  author = {Elizabeth Eepho Krukru and Bruno Chukwuemeka Chinko and Victor Datonye Dapper},
  title = {Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model},
  journal = {Biomedical Sciences},
  volume = {12},
  number = {1},
  pages = {10-16},
  doi = {10.11648/j.bs.20261201.12},
  url = {https://doi.org/10.11648/j.bs.20261201.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.bs.20261201.12},
  abstract = {Brain-derived neurotrophic factor (BDNF) is a critical regulator of neuronal survival, synaptic plasticity, and cognitive function, making it a key biomarker in understanding the neurobiological impact of opioid exposure. This study investigated the effects of opioids (codeine and tramadol) on brain-derived neurotrophic factor (BDNF) levels in male Wistar rats. A total of 75 male Wistar rats (120-140g) were used for the study in acute, sub-chronic and chronic phases, using 25 rats for each phase. In each phase, 25 male Wistar rats were divided into 5 groups of 5 animals each. Group 1 served as the control and received distilled water, groups 2 and 3 were treated with tramadol at 20 and 60 mg/kg, respectively, while groups 4 and 5 were supplemented with codeine at 10 and 30 mg/kg, respectively. Treatment by oral gavage lasted for 14, 28 and 56 days for the acute, sub-chronic and chronic studies, respectively. Serum and hippocampal BDNF assays were analysed following standard laboratory protocols. Results showed dose and time-dependent significant reductions (p < 0.05) in BDNF levels across all treatment groups compared to controls, with the most pronounced decreases observed in codeine 30mg/kg and tramadol 60mg/kg groups. These findings suggest that prolonged opioid exposure disrupts neurotrophic signalling, potentially contributing to neurodegenerative conditions.},
 year = {2026}
}

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TY  - JOUR
T1  - Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model
AU  - Elizabeth Eepho Krukru
AU  - Bruno Chukwuemeka Chinko
AU  - Victor Datonye Dapper
Y1  - 2026/02/21
PY  - 2026
N1  - https://doi.org/10.11648/j.bs.20261201.12
DO  - 10.11648/j.bs.20261201.12
T2  - Biomedical Sciences
JF  - Biomedical Sciences
JO  - Biomedical Sciences
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EP  - 16
PB  - Science Publishing Group
SN  - 2575-3932
UR  - https://doi.org/10.11648/j.bs.20261201.12
AB  - Brain-derived neurotrophic factor (BDNF) is a critical regulator of neuronal survival, synaptic plasticity, and cognitive function, making it a key biomarker in understanding the neurobiological impact of opioid exposure. This study investigated the effects of opioids (codeine and tramadol) on brain-derived neurotrophic factor (BDNF) levels in male Wistar rats. A total of 75 male Wistar rats (120-140g) were used for the study in acute, sub-chronic and chronic phases, using 25 rats for each phase. In each phase, 25 male Wistar rats were divided into 5 groups of 5 animals each. Group 1 served as the control and received distilled water, groups 2 and 3 were treated with tramadol at 20 and 60 mg/kg, respectively, while groups 4 and 5 were supplemented with codeine at 10 and 30 mg/kg, respectively. Treatment by oral gavage lasted for 14, 28 and 56 days for the acute, sub-chronic and chronic studies, respectively. Serum and hippocampal BDNF assays were analysed following standard laboratory protocols. Results showed dose and time-dependent significant reductions (p < 0.05) in BDNF levels across all treatment groups compared to controls, with the most pronounced decreases observed in codeine 30mg/kg and tramadol 60mg/kg groups. These findings suggest that prolonged opioid exposure disrupts neurotrophic signalling, potentially contributing to neurodegenerative conditions.
VL  - 12
IS  - 1
ER  -

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Author Information

Elizabeth Eepho Krukru

Department of Human Physiology, Rivers State University, Port Harcourt, Nigeria

Contact Email

http://orcid.org/0009-0005-5698-2394
Bruno Chukwuemeka Chinko

Department of Human Physiology, University of Port Harcourt, Port Harcourt, Nigeria

http://orcid.org/0000-0002-0457-2853
Victor Datonye Dapper

Department of Human Physiology, University of Port Harcourt, Port Harcourt, Nigeria

http://orcid.org/0000-0002-1617-1686

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Krukru, E. E., Chinko, B. C., Dapper, V. D. (2026). Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model. Biomedical Sciences, 12(1), 10-16. https://doi.org/10.11648/j.bs.20261201.12

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ACS Style

Krukru, E. E.; Chinko, B. C.; Dapper, V. D. Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model. Biomed. Sci. 2026, 12(1), 10-16. doi: 10.11648/j.bs.20261201.12

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AMA Style

Krukru EE, Chinko BC, Dapper VD. Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model. Biomed Sci. 2026;12(1):10-16. doi: 10.11648/j.bs.20261201.12

Copy | Download

@article{10.11648/j.bs.20261201.12,
  author = {Elizabeth Eepho Krukru and Bruno Chukwuemeka Chinko and Victor Datonye Dapper},
  title = {Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model},
  journal = {Biomedical Sciences},
  volume = {12},
  number = {1},
  pages = {10-16},
  doi = {10.11648/j.bs.20261201.12},
  url = {https://doi.org/10.11648/j.bs.20261201.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.bs.20261201.12},
  abstract = {Brain-derived neurotrophic factor (BDNF) is a critical regulator of neuronal survival, synaptic plasticity, and cognitive function, making it a key biomarker in understanding the neurobiological impact of opioid exposure. This study investigated the effects of opioids (codeine and tramadol) on brain-derived neurotrophic factor (BDNF) levels in male Wistar rats. A total of 75 male Wistar rats (120-140g) were used for the study in acute, sub-chronic and chronic phases, using 25 rats for each phase. In each phase, 25 male Wistar rats were divided into 5 groups of 5 animals each. Group 1 served as the control and received distilled water, groups 2 and 3 were treated with tramadol at 20 and 60 mg/kg, respectively, while groups 4 and 5 were supplemented with codeine at 10 and 30 mg/kg, respectively. Treatment by oral gavage lasted for 14, 28 and 56 days for the acute, sub-chronic and chronic studies, respectively. Serum and hippocampal BDNF assays were analysed following standard laboratory protocols. Results showed dose and time-dependent significant reductions (p < 0.05) in BDNF levels across all treatment groups compared to controls, with the most pronounced decreases observed in codeine 30mg/kg and tramadol 60mg/kg groups. These findings suggest that prolonged opioid exposure disrupts neurotrophic signalling, potentially contributing to neurodegenerative conditions.},
 year = {2026}
}

Copy | Download

TY  - JOUR
T1  - Opioid-Induced Dysregulation of BDNF Signalling: A Study of Acute, Sub-Chronic, and Chronic Exposure in a Rodent Model
AU  - Elizabeth Eepho Krukru
AU  - Bruno Chukwuemeka Chinko
AU  - Victor Datonye Dapper
Y1  - 2026/02/21
PY  - 2026
N1  - https://doi.org/10.11648/j.bs.20261201.12
DO  - 10.11648/j.bs.20261201.12
T2  - Biomedical Sciences
JF  - Biomedical Sciences
JO  - Biomedical Sciences
SP  - 10
EP  - 16
PB  - Science Publishing Group
SN  - 2575-3932
UR  - https://doi.org/10.11648/j.bs.20261201.12
AB  - Brain-derived neurotrophic factor (BDNF) is a critical regulator of neuronal survival, synaptic plasticity, and cognitive function, making it a key biomarker in understanding the neurobiological impact of opioid exposure. This study investigated the effects of opioids (codeine and tramadol) on brain-derived neurotrophic factor (BDNF) levels in male Wistar rats. A total of 75 male Wistar rats (120-140g) were used for the study in acute, sub-chronic and chronic phases, using 25 rats for each phase. In each phase, 25 male Wistar rats were divided into 5 groups of 5 animals each. Group 1 served as the control and received distilled water, groups 2 and 3 were treated with tramadol at 20 and 60 mg/kg, respectively, while groups 4 and 5 were supplemented with codeine at 10 and 30 mg/kg, respectively. Treatment by oral gavage lasted for 14, 28 and 56 days for the acute, sub-chronic and chronic studies, respectively. Serum and hippocampal BDNF assays were analysed following standard laboratory protocols. Results showed dose and time-dependent significant reductions (p < 0.05) in BDNF levels across all treatment groups compared to controls, with the most pronounced decreases observed in codeine 30mg/kg and tramadol 60mg/kg groups. These findings suggest that prolonged opioid exposure disrupts neurotrophic signalling, potentially contributing to neurodegenerative conditions.
VL  - 12
IS  - 1
ER  -

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