Oral L-glutamine administration attenuated cutaneous wound healing in Wistar rats

Abstract

The objective of this study was to evaluate the wound healing potential of L-glutamine in laboratory rats using excision and incision wound models. Excision wounds of size 500 mm(2) and depth 2 mm were made on the dorsal portion of male Wistar rats (230-250 g) and were used for the study of oral L-glutamine (1 g/kg) treatment on the rate of contraction of wound and epithelisation. Histological evaluation of wound tissue was also performed. Six-centimetre-long two linear-paravertebral incisions in male Wistar rats (230-250 g) were used to study the effect of L-glutamine (1 g/kg, p.o.) treatment on tensile strength, total protein and hydroxyproline content in the incision model. Oral administration of L-glutamine (1 g/kg) significantly decreased wound area, epithelisation period and wound index, whereas the rate of wound contraction significantly increased (P < 0·001) when compared with vehicle control rats in the excision wound model. Tensile strength, hydroxyproline content and protein level were significantly increased (P < 0·001) in L-glutamine (1 g/kg, p.o.)-treated rats when compared with vehicle control rats in the incision wound model. Histological evaluation of wound tissue from L-glutamine (1 g/kg, p.o.)-treated rats showed complete epithelialisation with new blood vessel formation and high fibrous tissues in the excision wound model. In conclusion, oral administration of l-glutamine (1 g/kg) promotes wound healing by acting on various stages of wound healing such as collagen synthesis, wound contraction and epithelialisation.

Keywords: Excision wounds; Hydroxyproline; Incision wounds; Tensile strength; l-Glutamine.

Figure 1

Effect of glutamine treatment on wound area (mm²) (A) and rate of wound contraction (B) in rats. Data are expressed as mean ± SEM from six rats and analysed by two‐way analysis of variance followed by Bonferroni's test. *P < 0·05, **P < 0·01, ***P < 0·001 when compared with vehicle control group animals.

Figure 2

Photographs of rats showing the effect of glutamine administration on various phases of wound healing in the excision model.

Figure 3

Photographs of rats showing the effect of glutamine administration on wound healing in the incision model.

Figure 4

Photomicrographs of the sections of skin from rats stained with haematoxylin (H) and eosin (E) in the excision model. Images (100× magnification) are typical and representative of each study group.