Postoperative pain and analgesic responses are similar in male and female Sprague-Dawley rats (original) (raw)

Abstract

Purpose

Controversy exists concerning the influence of gender on pain sensitivity and response to analgesics both in animal and human studies. The present study compares postoperative pain scores in male and female rats and how they respond to analgesic interventions.

Methods

Unilateral plantar foot incisions were made in Sprague-Dawley rats of both genders, producing mechanical allodynia in an established model of postoperative pain. Postoperative pain scores were monitored for four days following incision to identify intrinsic differences between the two groups. Animals were tested with analgesics (opioids, α2-adrenergic agonists, acetylcholine esterase inhibitors, gabapentin) both systemically and intrathecally on the day after incision to assess gender differences in the anti-allodynic effect of these drugs.

Results

In the plantar foot incision model of postoperative pain there was no gender difference in postoperative mechanical hypersensitivity (von Frey filaments) over four days. Morphine (3 mg · kg−1) and gabapentin (25 mg · kg−1) administered intraperitoneally decreased postoperative mechanical hypersensitivity, but with no gender difference. Intrathecal morphine (1–2 nmol), gabapentin (60–120 nmol), clonidine (45 nmol), and neostigmine (6.6 nmol) also showed no gender difference in analgesic effect.

Conclusion

The results of this study demonstrate that in Sprague-Dawley rats there are no gender differences in postoperative pain perception or the response to analgesics, indicating that this strain of rats can be used without introducing gender bias in studies of postoperative pain.

Résumé

Objectif

L’influence du sexe sur la sensibilité à la douleur et la réaction aux analgésiques ne fait pas l’unanimité dans les études chez l’animal et chez l’humain. La présente étude compare les scores de douleur postopératoire et la réaction aux analgésiques entre des rats et des rates.

Méthode

Des incisions unilatérales à la plante du pied ont été faites chez des rats et des rates Sprague-Dawley, ce qui a produit une allodynie mécanique selon un modèle connu de douleur postopératoire. Les scores de douleur postopératoire ont été enregistrés pendant quatre jours après les incisions afin d’établir des différences intrinsèques entre les deux groupes. Les animaux ont été testés avec des analgésiques (opioïdes, agonistes α2-adrénergiques, inhibiteurs de l’acétylcholine estérase, gabapentine) systémiques et intrathécaux le jour suivant l’incision pour évaluer les différences de l’effet anti-allodynique de ces médicaments selon le sexe de l’animal.

Résultats

Chez le modèle de douleur postopératoire avec incision plantaire, il n’y avait pas de différence d’hypersensibilité mécanique postopératoire (filaments von Frey) reliée au sexe. Avec l’administration intrapéritonéale de morphine (3 mg · kg−1 ) et de gabapentine (25 mg· kg−1), l’hypersensibilité mécanique postopératoire a été réduite, sans différence entre les sexes. Ladministration intrathécale de morphine (1–2 nmol), de gabapentine (60–120 nmol), de clonidine (45 nmol) et de néostigmine (6,6 nmol) n’a pas montré non plus de différence d’effet analgésique reliée au sexe.

Conclusion

Les résultats de l’étude démontrent que chez les rats Sprague-Dawley, il n’y a pas de différence reliée au sexe quant à la perception de la douleur postopératoire ou à la réaction aux analgésiques, ce qui indique qu’on peut utiliser cette lignée de rats pour des études sur la douleur postopératoire sans devoir introduire le biais du sexe.

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Authors and Affiliations

  1. Department of Anesthesiology, Rush Medical College, 1653 West Congress Parkway, 60612, Chicago, IL, USA
    Jeffrey S. Kroin, Asokumar Buvanendran, Subhash K. S. Nagalla & Kenneth J. Tuman

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  1. Jeffrey S. Kroin
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  2. Asokumar Buvanendran
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  3. Subhash K. S. Nagalla
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  4. Kenneth J. Tuman
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Correspondence toJeffrey S. Kroin.

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Kroin, J.S., Buvanendran, A., Nagalla, S.K.S. et al. Postoperative pain and analgesic responses are similar in male and female Sprague-Dawley rats.Can J Anesth 50, 904–908 (2003). https://doi.org/10.1007/BF03018737

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