Cell Apoptosis of Taste Buds in Circumvallate Papillae in Diabetic Rats

Abstract

Diabetes mellitus may result in taste disturbance. The present study has revealed that cell apoptosis of taste buds in circumvallate papillae may contribute to the taste disturbance in a rat model of type2 diabetes. Type2 diabetes was induced in Wistar rats by feeding them with a high-fat diet (30% fat), and a single intraperitoneal injection of streptozotocin (30 mg/kg). The increased cell apoptosis of taste buds in circumvallate papilla sections was detected by TUNEL staining in diabetic rats, and the ultrastructure was further examined by transmission electronic microscopy. Immunohistochemical and Western blot analyses revealed the downregulation of Bcl-2, upregulation of Bax, and increased activation of caspase-9 and -3, in diabetic rats, indicating that the apoptosis of taste bud cells may be mediated via the intrinsic mitochondrial pathway in diabetics.

Key words

type 2 diabetes - taste buds - apoptosis - bcl-2 - caspase

References

• 1 Assis GF, Ceolin DS, Marques ME. et al . A Cigarette smoke affects apoptosis in rat tongue mucosa: role of bcl-2 gene family.  J Mol Hist. 2005;  36 483-489
• 2 Green DR, Kroemer G. The pathophysiology of mitochondrial cell death.  Science. 2004;  305 626-629
• 3 Hardy SL, Brennand CP, Wyse BW. Taste thresholds of individuals with diabetes mellitus and of control subjects.  J Am Diet Assoc. 1981;  79 286-289
• 4 Hengartner MO. The biochemistry of apoptosis.  Nature. 2000;  407 770-776
• 5 Henkin RI, Hoetker JD. Deficient dietary intake of vitamin E in patients with taste and smell dysfunctions: is vitamin E a cofactor in taste bud and olfactory epithelium apoptosis and in stem cell maturation and development?.  Nutrition. 2003;  19 1013-1021
• 6 Huang YJ, Lu KS. TUNEL staining and electron microscopy studies of apoptotic changes in the guinea pig vallate taste cells after unilateral glossopharyngeal denervation.  Anat Embryol (Berl). 2001;  204 493-501
• 7 Ichimori Y, Ueda K, Okada H. et al . Histochemical changes and apoptosis in degenerating taste buds of the rat circumvallate papilla.  Arch Histol Cytol. 2009;  72 91-100
• 8 Le Floch JP, LeLie`vre G, Labroue M. et al . Early detection of diabetic patients at risk of developing degenerative complications using electric gustometry: a five-year follow-up study.  Eur J Med. 1992;  1 208-214
• 9 Loro L, Vintermyr OK, Johannessen AC. Apoptosis in normal and diseased oral tissues.  Oral Dis. 2005;  11 274-287
• 10 Miquel C, Borrini F, Grandjouan S. et al . Role of bax mutations in apoptosis in colorectal cancers with microsatellite instability.  Am J Clin Pathol. 2005;  123 562-570
• 11 Pai MH, Ko TL, Chou HC. Effects of streptozotocin-induced diabetes on taste buds in rat vallate papillae.  Acta Histochem. 2007;  109 200-207
• 12 Schelling JL, Tetreault L, Lasagna L. et al . Abnormal taste threshold in diabetes.  Lancet. 1965;  1 508-512
• 13 Srinivasan K, Viswanad B, Asrat L. et al . Combination of high-fat diet-fed and low-dose streptozotocin-treated rat: a model for type2 diabetes and pharmacological screening.  Pharmacol Res. 2005;  52 313-320
• 14 Takeda M, Suzuki Y, Obara N. et al . Induction of apoptosis by colchicine in taste bud and epithelial cells of the mouse circumvallate papillae.  Cell Tissue Res. 2000;  302 391-395
• 15 Walensky LD. BCL-2 in the crosshairs: tipping the balance of life and death.  Cell Death Differ. 2006;  13 1339-1350
• 16 Wang H, Zhou M, Brand J. et al . Inflammation and taste disorders: mechanisms in taste buds.  Ann N Y Acad Sci. 2009;  1170 596-603
• 17 Yang J, Liu X, Bhalla K. et al . Prevention of apoptosis by Bcl-2: release of cytochrome c from mitochondria blocked.  Science. 1997;  275 1129-1132
• 18 Zeng Q, Oakley B. p53 and Bax: putative death factors in taste cell turnover.  J Comp Neurol. 1999;  413 168-180
• 19 Zeng Q, Kwan A, Oakley B. Gustatory innervation and bax-dependent caspase-2: participants in the life and death pathways of mouse taste receptor cells.  J Comp Neurol. 2000;  424 640-650
• 20 Zhou LH, Liu XM, Feng XH. et al . Expression of alpha-gustducin in the circumvallate papillae of taste buds of diabetic rats.  Acta Histochem. 2009;  111 145-149

Correspondence