Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jul 7;7(7):e07500.
doi: 10.1016/j.heliyon.2021.e07500. eCollection 2021 Jul.

Refinement of the spinal cord injury rat model and validation of its applicability as a model for memory loss and chronic pain

V S Harikrishnan  1   2 , Hamza Palekkodan  3 , Ansar Fasaludeen  3 , Lissy K Krishnan  4 , Klas S P Abelson  2
Affiliations

Refinement of the spinal cord injury rat model and validation of its applicability as a model for memory loss and chronic pain

V S Harikrishnan et al. Heliyon. .

Abstract

Background: Laminectomy produces trauma in spinal cord injury (SCI) animal models resulting in impinging artefacts and welfare issues. Mechanizing laminectomy using a dental burr assisted (DBA) technique to reduce the impact of conventionally performed laminectomy on animal welfare without any alterations in the outcome of the model was previously demonstrated. However, further validation was necessary to establish it as an alternative in developing SCI rats as a model of chronic pain and memory loss.

Novel method: DBA technique was employed to perform laminectomy at T10-T11 vertebrae in rats undergoing contusion SCI as a model of chronic pain and memory loss. In a 56-day study, 24 female Wistar rats (Crl: WI) were assigned randomly to four equal groups: conventionally laminectomised, DBA laminectomised, conventionally laminectomised with SCI and DBA laminectomised with SCI.

Results: The study revealed DBA technique to cause less surgical bleeding (p = 0.001), lower Rat Grimace Scale (p = 0.0006); resulted in better body weight changes (p = 0.0002 on Day 7 and p = 0.0108 on Day 28) and dark phase activity (p = .0.0014 on Day 1; p = 0.0422 on Day 56). Different techniques did not differ in Basso Beattie Bresnahan score, novel object recognition, mechanical allodynia, number of surviving neurons and the area of vacuolation- indicating that the new method doesn't affect the validity of the model.

Comparison with existing methods: In comparison with the conventional technique, motorised laminectomy can be a valid tool that evokes lesser pain and ensures higher well-being in rats modelled for chronic pain and memory loss.

Conclusions: The intended outcome from the model is not influenced by techniques whereas the DBA-technique is a refined alternative to the conventional method in achieving better welfare in SCI studies.

Keywords: BBB score; Chronic pain; Dental burr assisted laminectomy; Memory loss; Rat model; Refinement; Spinal cord injury.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Intra-operative bleeding scores comparison. Bleeding scores comparison of rats (n = 6 per group) subjected to laminectomy using conventional (CONV-LAM) or motorised dental burr assisted (DBA-LAM) technique during the surgery. Scores differed between groups as determined by Kruskal-Wallis test with Dunn’s multiple comparisons. Data are presented as scatter plot with each dot representing one animal, the horizontal line the mean and the whiskers the standard deviation. ∗∗ = P < 0.01.
Figure 2
Figure 2
Post-operative BBB score comparison. BBB scores of rats (n = 6 per group) subjected to laminectomy using conventional (CONV-LAM) or motorized dental burr assisted (DBA-LAM) technique at, or subjected to spinal cord injury-induced using conventional (CONV-SCI) or dental burr assisted (DBA-SCI) technique during the study period. Scores differed between groups on Day 1 (A), Day 7 (B), Day 14 (C), Day 21 (D), Day 28 (E) and Day 56 (F) postoperatively as determined by Kruskal-Wallis test with Dunn’s multiple comparisons. Data are presented as scatter plot with each dot representing one individual animal, the horizontal line the mean and the whiskers the standard deviation. ∗∗ = P < 0.01.
Figure 3
Figure 3
Post-operative body weights comparison. Postoperative weight fluctuation (compared to the initial body weights) in rats (n = 6 per group) subjected to laminectomy using conventional (CONV-LAM) or motorized dental burr assisted (DBA-LAM) technique, or subjected to spinal cord injury induced using conventional (CONV-SCI) or dental burr assisted (DBA-SCI) technique during the study period on Day 1 (A), Day 7 (B), Day 14 (C), Day 21 (D), Day 28 (E) and Day 56 (F) postoperatively. Differences were analysed by Kruskal-Wallis test with Dunn’s multiple comparisons on Day 1 and by ANOVA with Tukey’s multiple comparisons on Days 7, 14, 21, 28 and 56. Data are presented as scatter plot with each dot representing one individual animal, the horizontal line the mean and the whiskers the standard deviation. ∗ = P < 0.05.
Figure 4
Figure 4
Post-operative RGS scores comparison. Change of RGS scores from baseline values of rats (n = 6 per group) subjected to laminectomy using conventional (CONV-LAM) or motorized dental burr assisted (DBA-LAM) technique at, or subjected to spinal cord injury induced using conventional (CONV-SCI) or dental burr assisted (DBA-SCI) technique during the study period. RGS scores differed significantly on Day 1 (A) post-operatively between groups, as determined by Kruskal-Wallis test with Dunn’s multiple comparisons. No differences between groups were observed Day 7(B), 14 (C), 21 (D), Day 28 (E) or Day 56 (F). Data are presented as a scatter plot with each dot representing one individual animal, the horizontal line the mean and the whiskers the standard deviation. ∗∗∗ = P < 0.001.
Figure 5
Figure 5
Home cage activity in the dark phase. Home cage activity time in dark phase of rats (n = 6 per group) subjected to laminectomy using conventional (CONV-LAM) or motorized dental burr assisted (DBA-LAM) technique, or subjected to spinal cord injury induced using conventional (CONV-SCI) or dental burr assisted (DBA-SCI) technique during the study period. Time of activity differed significantly between groups on Day 1 (A) as determined by ANOVA with Tukey’s multiple comparisons and on Day (F) 56 as determined by Kruskal-Wallis test with Dunn’s multiple comparisons. Differences were analysed by ANOVA with Tukey’s multiple comparisons on Day 1 and by Kruskal-Wallis test with Dunn’s multiple comparisons on Days 7, 14, 21, 28 and Day 56. No differences between groups were observed Day 7(B), 14 (C), 21 (D) and Day 28 (E). Data are presented as a scatter plot with each dot representing one individual animal, the horizontal line the mean and the whiskers the standard deviation. ∗ = P < 0.05, ∗∗ = P < 0.01.
Figure 6
Figure 6
Home cage rearing score in dark phase. Rearing scores of rats in their home cage during the dark phase (n = 6 per group) subjected to laminectomy using conventional (CONV-LAM) or motorized dental burr assisted (DBA-LAM) technique, or subjected to spinal cord injury induced using conventional (CONV-SCI) or dental burr assisted (DBA-SCI) technique during the study period. Time of activity differed significantly between groups on Day 1 (A) as determined by ANOVA with Tukey’s multiple comparisons. Differences were analysed by ANOVA with Tukey’s multiple comparisons on Day 1(A) and 14(C) and by Kruskal-Wallis test with Dunn’s multiple comparisons on Days 7 (B), 21(D), 28(E) and 56(F). Rearing score in home cage during dark phase differed significantly on Day 1 (A) whereas no differences between groups were observed Days 7(B), 14 (C), 21 (D), Day 28 (E) or Day 56 (F). ∗ = P < 0.05.
Figure 7
Figure 7
Representative slides from H and E stained (40X) sections. Representative slides from H and E stained (40X) sections. (a) CONV-LAM (b) DBA-LAM (c) CONV-SCI and (d) DBA-SCI.
Figure 8
Figure 8
Representative slides from Cresyl Violet (Nissl’s) stained (40X) sections. (A) CONV-LAM (b) DBA-LAM (c) CONV-SCI, and (d) DBA-SCI.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Bickenbach J., Officer A., Shakespeare T., von Groote P., Organization W.H. World Health Organization; 2013. International Perspectives on Spinal Cord Injury.
    1. Sharif-Alhoseini M., Khormali M., Rezaei M., Safdarian M., Hajighadery A., Khalatbari M., Meknatkhah S., Rezvan M., Chalangari M., Derakhshan P. Animal models of spinal cord injury: a systematic review. Spinal Cord. 2017;55(8):714–721. - PubMed
    1. Hosier H., Peterson D., Tsymbalyuk O., Keledjian K., Smith B.R., Ivanova S., Gerzanich V., Popovich P.G., Simard J.M. A direct comparison of three clinically relevant treatments in a rat model of cervical spinal cord injury. J. Neurotrauma. 2015;32(21):1633–1644. - PMC - PubMed
    1. Chiu C., Cheng H., Hsieh S. Contusion spinal cord injury rat model. Bio-protocol. 2017;7(12) - PMC - PubMed
    1. Onifer S.M., Rabchevsky A.G., Scheff S.W. Rat models of traumatic spinal cord injury to assess motor recovery. ILAR J. 2007;48(4):385–395. - PubMed

LinkOut - more resources