Wound healing mechanisms in rats with streptozotocin-induced diabetes mellitus

Background. Wound healing disorders and formation of diabetic foot, a severe disabling complication of diabetes mellitus, are accompanied by nervous system impairment and/or ischemia.

Objective — the study was aimed at assessing the effect of peripheral innervation disorders on the regulation of tissue repair in the streptozotocin-induced rat model of diabetes mellitus.

Material and methods. The study was carried out in male white outbred rats (n=70). The animals were wounded 42 days after induction of diabetes by injecting streptozotocin (diabetes group; this group received insulin Levemir at a dose of 2 units/kg in saline subcutaneously to reduce mortality), or after injection of citrate buffer (CB group). Skin samples were taken on day 8, 16, and 24 after wound modeling. Pain sensitivity was assessed in all animals. The resulting skin fragments were fixed, dehydrated, and embedded in paraffin according to standard procedures. Sections were stained with hematoxylin and eosin, antibodies specific for Ki-67, α₁, β₁, and β₂-adrenoreceptors were used for immunohistochemical staining. Intact animals were used as an additional control group.

Results. Tail withdrawal time measured on day 56 was higher in DM group rats as compared to the control group (p=0.017). CB group demonstrated a tendency towards more rapid wounds healing than diabetic animals, although the difference was not statistically significant due to wide scatter of data in the DM group (p=0.64). The intensity of staining for Ki67 was lower in the DM group (p=0.045). Reduced density of β₂-adrenoreceptors was observed at the areas remote from the wound in CB group rats.

Conclusion The results show no correlation between altered innervation and impaired tissue repair in rats with streptozotocin-induced diabetes.

peripheral neuropathy, streptozotocin-induced diabetes, tissue repair, nervous regulation, keratinocytes

1. Токмакова А.Ю., Страхова Г.Ю., Арбузова М.И. Особенности хронических ран у больных сахарным диабетом и пути их коррекции. // Эндокринная хирургия. — 2007. — Т. 1. — № 1. — C. 38—42. [Tokmakova AYu, Strakhova GYu, Arbuzova MI. Osobennosti khronicheskikh ran u bol’nykh sakharnym diabetom i puti ikh korrektsii. Endocrine Surgery. 2007;1(1):38-42. (In Russ.)]. doi: https://doi.org/10.14341/2306-3513-2007-1-38-42

2. Garwood CS, Steinberg JS, Kim PJ. Bioengineered alternative tissues in diabetic wound healing. Clin Podiatr Med Surg. 2015; 32(1):121-133. doi: https://doi.org/10.1016/j.cpm.2014.09.004

3. Demidova-Rice TN, Hamblin MR, Herman IM. Acute and impaired wound healing: pathophysiology and current methods for drug delivery, part 1: normal and chronic wounds: biology, causes, and approaches to care. Adv Skin Wound Care. 2012;25(7):304-314. doi: https://doi.org/10.1097/01.asw.0000416006.55218.d0

4. Roosterman D, Goerge T, Schneider SW, et al. Neuronal control of skin function: the skin as a neuroimmunoendocrine organ. Physiol Rev. 2006;86(4):1309-1379. doi: https://doi.org/10.1152/physrev.00026.2005

5. Grando SA, Pittelkow MR, Schallreuter KU. Adrenergic and cholinergic control in the biology of epidermis: physiological and clinical significance. J Invest Dermatol. 2006;126(9):1948-1965. doi: https://doi.org/10.1038/sj.jid.5700151

6. Grando SA, Kist DA, Qi M, Dahl MV. Human Keratinocytes Synthesize, Secrete, And Degrade Acetylcholine. J Invest Dermatol. 1993;101(1):32-36. doi: http//doi.org/10.1111/1523-1747.ep12358588.7

7. Inoue R, Yoshihisa Y, Tojo Y, et al. Localization of serine racemase and its role in the skin. J Invest Dermatol. 2014;134(6):1618-1626. doi: https://doi.org/10.1038/jid.2014.22

8. Pullar CE, Manabat-Hidalgo CG, Bolaji RS, Isseroff RR. Beta-Adrenergic receptor modulation of wound repair. Pharmacol Res. 2008;58(2):158-164. doi: https://doi.org/10.1016/j.phrs.2008.07.012

9. Ramaekers G, Lamers J, Verhey F, et al. A comparative study of the effects of carbamazepine and the NMDA receptor antagonist remacemide on road tracking and car-following performance in actual traffic. Psychopharmacology (Berl). 2002;159(2):203-210. doi: https://doi.org/10.1007/s002130100898

10. Biessels GJ, Bril V, Calcutt NA, et al. Phenotyping animal models of diabetic neuropathy: a consensus statement of the diabetic neuropathy study group of the EASD (Neurodiab). J Peripher Nerv Syst. 2014;19(2):77-87. doi: https://doi.org/10.1111/jns5.12072

11. Румянцев П.О., Саенко В.А., Румянцева У.В. и др. Статистические методы анализа в клинической практике. Часть 2. Анализ выживаемости и многомерная статистика. // Проблемы эндокринологии. — 2009. — № 55(6). — C. 48—56. [Rumyantsev PO, Saenko VA, Rumyantseva UV, et al. Statistical methods for the analyses in clinical practice. Part 2. Survival analysis and multivariate statistics. Problems of Endocrinology. 2009;55(6):48-56. (In Russ.)]. doi: https://doi.org/10.14341/probl200955648-56

12. Yorek MA. Alternatives to the streptozotocin-diabetic rodent. Int Rev Neurobiol. 2016;127:89-112. doi: https://doi.org/10.1016/bs.irn.2016.03.002