Angiotensin change overing enzyme ( ACE ) inhibitors are known to increase the degree of bradykinin by forestalling its dislocation and besides promote prostaglandin synthesis by direct and indirect methods which in bend may advance wound mending. However there is dearth of scientific information in this respect. Therefore in the present survey we have investigated the consequence of ACE inhibitors like Captopril and Enalapril on different lesion theoretical accounts in Wistar rats. Deletion, resutured scratch and dead infinite lesions were inflicted in male Wistar rats under visible radiation ether anesthesia, taking sterile safeguards. Control animate beings received vehicle and other groups received Captopril ( 10mg/kg ) and Enalapril ( 10mg/kg ) orally for a period of 10 yearss in scratch and dead infinite lesion theoretical accounts, whereas similar interventions were continued in deletion lesion theoretical accounts till complete closing of lesions.
On the 11th twenty-four hours, after gauging interrupting strength of resutured scratch lesions ( under anesthesia ) , granulation tissue was removed from dead infinite lesions to gauge breakage strength, hydroxyproline content every bit good as quantification of granulation tissue and histological surveies were carried out in control and treated groups. Captopril and Enalapril significantly increased the rate of lesion healing, reduced the figure of yearss required for complete epithelialization and concluding country of cicatrix in deletion lesions. Both the ACE inhibitors significantly increased interrupting strength of resutured scratch lesions and granulation tissue. Besides these two drugs significantly enhanced both granulation tissue formation and granulation tissue hydroxyproline content.
Histological surveies confirmed these findings. Captopril and Enalapril significantly promoted the healing procedure in all the three lesion theoretical accounts studied. These consequences indicate the lesion mending belongings of ACE inhibitors and clinical surveies in this respect are worthwhile.Cardinal words: Captopril, Dead infinite lesions, Enalapril, Excision wounds, Healing, Incisionlesions.
Wound has been defined as break of anatomic or functional continuity of life tissue ( Schilling,1968 ) produced by physical, chemical, electrical or microbic abuse to the tissue and lesion mending refers to the Restoration of the continuity of life tissue.
The healing of lesion follows a general strategy in which a sequence of procedures takes topographic point in an orderly manner viz. , inflammatory stage, proliferative stage and remodelling stage ( Clark and Henson,1988 ; Kanzler et al.,1986 ; Goslen,1988 ; Wahl et al.
,2004 ; McKay and Leigh,1991 ) . The inflammatory stage is marked by vasodilatation, increased vascular permeableness, thrombocyte accretion and curdling and leucocytic migration ( Kumar,2004 ) . Bradykinin, an of import go-between of redness, apart from doing vasodilatation and hydrops is known to excite angiogenesis ( Hu and Fan,1993 ) and proliferation of fibroblasts by interacting with inflammatory cytokine interleukins-I ( Kimball and Fisher,1988 ) and besides it has been reported that kinins are known to let go of cytokines, interleukin – I and tumour mortification factor ( Tiffany and Burch,1989 ) which are known to excite fibroblast proliferation ( Kahaleh et al.
,1988 ) . Kinins are known to excite release of histamine from mast cells which in bend is known to excite stomachic parietal cells ( Cambel and Sgouris,1952 ) and hair follicle cells ( Butcher,1940 ) . It has been besides reported that kinins act straight as mitogens exciting DNA synthesis and thereby advance cell proliferation ( Whitfield et al.
,1970 ; Owen and Villereal,1983 ) .Angiotensin change overing enzyme ( ACE ) , an enzyme discovered serendipitously in plasma as a factor responsible for transition of angiotensin – I to angiotensin – II is known to demobilize bradykinin and other potent vasodilative peptides. This enzyme is known to be present throughout the vascular system peculiarly it is abundant in lung and tegument ( Regoli and Barabe,1980 ) . Therefore ACE inhibitors are known to increase bradykinin degrees by suppressing its dislocation ( Yang et al.,1970 ) and besides straight stimulate prostaglandin release ( Zusman,1981 ; Stephen,1982 ) thereby increasing the degrees of bradykinin and prostaglandin. These drugs in bend may favor the procedure of lesion healing, as described before. As ACE inhibitors are the drugs used for drawn-out periods in chronic diseases like high blood pressure, ischaemic bosom disease and congestive bosom failure, it is desirable to cognize the influence of these drugs on lesion healing.
However there is dearth of literature sing the influence of ACE inhibitors on lesion healing. Hence the present survey was undertaken to look into the influence of normally used ACE inhibitors like Capoten and Vasotec in their clinically tantamount doses on healing of three different theoretical accounts of lesions in Wistar rats.
Materials and methods
Animals and drugs:
Healthy male Wistar rats weighing 150-250 g were housed separately, on standard pellet diet, with H2O ad libitum and were starved nightlong before the twenty-four hours of experimentation. Hairlessness at injuring site was done a twenty-four hours before injuring. After injuring, the animate beings were divided into control and intervention groups ( n = 6 in each ) for each lesion theoretical account to have assorted interventions. The clinical doses of the drugs were converted into rat tantamount doses, as calculated with the aid of the transition tabular array devised by ‘Paget and Barnes ‘ . ( Paget and Barnes,1964 ) The dosage of Captopril ( 10 mg/kg ) [ Lupin laboratories ] and Enalapril ( 10 mg/kg ) [ Dr.
Reddy ‘s research labs ] were dissolved into distilled H2O and were administered orally one time day-to-day at 8:00 ante meridiem, while control groups received equal volume of the vehicle. The continuance of the intervention was 10 yearss for animate beings inflicted with scratch and dead infinite lesions, whereas it was continued in animate beings bearing deletion lesion till their complete closing.
Deletion lesions were prepared by striking the full thickness round tegument ( about 500 mm2 ) from the scruff of cervix under quintessence anesthesia as described by Morton and Malone ( 1972 ) . Wound-closure rate and epithelialization clip were assessed by following the lesion on polythene paper from injuring twenty-four hours, followed by 4, 8, 12, 16 and 18th twenty-four hours and later on back-to-back yearss till complete epithelialization ( autumn of strikebreaker without any natural country ) . Similarly, cicatrixs were traced on complete epithelialization to measure wound contraction by observing cicatrix size and form.
Resutured scratch lesions were inflicted with two 6 centimeters long paravertebral analogue scratchs under visible radiation ether anaesthesia as described earlier ( Ehrlich and Hunt,1969 ) .
Sutures were removed on 7th twenty-four hours and on 10th station wounding twenty-four hours, interrupting strength was measured by the uninterrupted H2O flow technique as described by Lee ( 1968 ) .
Dead infinite lesion:
Imposition of dead infinite lesions were done by engrafting unfertile cotton pellets ( 10 milligram ) and cylindrical grass piths ( 2.5 centimeter A- 0.3 centimeter ) s.c. in the inguen and armpit instead by the technique of D’Arcy et Al. as described by Turner ( 1965 ) .
All the granulation tissues were removed under visible radiation ether anesthesia on 10th post-wounding twenty-four hours and dried at 60oC nightlong to enter the dry weight which was expressed as milligram per 100 g, organic structure weight as suggested by Dipasquale and Meli ( 1965 ) . As described earlier, one of the granulation tissues over the grass piths was opened and trimmed to a rectangular piece for appraisal of interrupting strength and later colorimetric appraisal of hydroxyproline content ( Woessner, 1961 ) . Histopathological surveies were conducted on the tissue covering the other grass pith. After remotion, the tissue was fixed in 10 % formol and processed to fix paraffin blocks. Sections were taken from these blocks and stained with haematoxylin and eosin. The slides were studied under microscope.All the processs were performed in conformity with the CPCSEA guidelines and the survey was approved by IAEC.
Datas were expressed as Mean A± SEM and analysed by one manner ANOVA followed by Dunnett ‘s trial.
P & lt ; 0.05 was considered as important.
Percentage closing of deletion wound country was significantly ( p & lt ; 0.01 and p & lt ; 0.001 ) enhanced at 4, 8, 12, 16 and 18 hours in both Capoten and Vasotec treated groups as compared to that of control group ( Table 1 ) . Number of yearss required for complete epithelialization were reduced significantly ( p & lt ; 0.001 ) in Capoten and Vasotec treated groups as compared to that of control group ( Table 1 ) .
On complete epithelialization the cicatrix forms in Capoten and Vasotec treated groups were significantly ( p & lt ; 0.001 ) smaller as compared to that of control group ( Table 1 ) .The breakage strength was significantly ( p & lt ; 0.
001 ) increased in Capoten and Vasotec treated animate beings both in resutured scratch lesion every bit good as granulation tissue as compared to condense H2O treated control group ( Table 2 ) . Both Capoten and Vasotec significantly ( p & lt ; 0.001 ) enhanced the granulation tissue formation ( Table 2 ) .The granulation tissue hydroxyproline content was significantly ( p & lt ; 0.001 ) more in Capoten and Vasotec treated animate beings as compared to that of control animate beings ( Table 2 ) .
Haematoxylin and eosin stained subdivisions of tissues over the grass piths when observed under light microscope revealed more figure of macrophages, fibroblasts and blood vass ( bespeaking granulation tissue ) in Vasotec and Capoten treated groups when compared with vehicle treated control group ( Fig 1 ) .
Table 1. Consequence of ACE inhibitors on deletion wound healing.
( n=6 )
& A ; Dose
( mg/kg )
Percentage closing of wound country
Time for complete epithelialization
( yearss )
( mm2 )
Mean A± SEM
Day – 4
Day – 8
Day – 12
Day – 16
Day – 18
1Control17.86 A±1.3849.83 A±2.4363.80 A±1.
8976.96 A±1.8192.67 A±1.8019.
83 A±0.4043.83 A±1.
512Captopril ( 10 )27.77 A±1.84*62.20 A±2.04*82.
43 A±2.19**94.20 A±1.89**99.13 A±0.
63*17.33 A±0.21**31.17 A±1.08**3Enalapril ( 10 )26.
40 A±2.10*60.47 A±2.15*81.63 A±2.12**93.16 A±1.84**98.
83 A±0.57*17.05 A±0.22**32.00 A±1.75**ANOVA followed by Dunnet ‘s trial, P & lt ; 0.01* , P & lt ; 0.
Table 2. Consequence of ACE inhibitors on scratch and dead infinite lesions.
( n=6 )
Drugs and Dose
( mg/kg )
Interrupting strength ( G )
Granulation tissue prohibitionist weight
( mg % b.w )
Granulation tissue hydroxyproline content ( mg/gm of tissue )
Resutured scratch lesions
Mean A± SEM
13329.17A±9.2643.33A±1.590.99A±0.022Captopril ( 10 )288.33A±10.
42A±0.02*3Enalapril ( 10 )282.50A±9.97*422.50A±8.33*60.52A±2.27*1.
37A±0.02*ANOVA followed by Dunnet ‘s trial, P & lt ; 0.001* .
Figure 1: Microphotographs of granulation tissues stained with H & A ; E ( 100 Ten ) .
Control ( vehicle ) [ H & A ; E – 100 X ] two ) Captopril ( 10 mg/kg ) [ H & A ; E – 100 Ten ]Enalapril ( 10 mg/kg ) [ H & A ; E – 100 Ten ]Note: Abundant granulation tissue is seen in Enalapril treated group ( three ) while moderate addition in granulation tissue is seen in Captopril treated group ( two ) when compared to vehicle treated control group ( I ) .
In the present survey two structurally different ACE inhibitors were investigated in their curative equivalent doses for their possible influence on lesion healing in different lesion theoretical accounts in Wistar rats.In deletion lesion survey, both Capotens and Vasotecs have significantly promoted wound contraction as evidenced by their consequence on lesion country throughout the survey. The average cicatrix country on complete epithelialization which indicates the extent of lesion contraction was significantly decreased in both Capoten and Vasotec treated groups as compared to that of control group. Both Capoten and Vasotec enhanced the epithelialization as evidenced by the important lessening in the clip required for complete epithelialization.The scratch wound theoretical account which represents surgical lesion in clinical pattern, where the contraction and epithelialization contribute least to the mending procedure in contrast to deletion lesion. Both Capoten and Vasotec have enhanced the healing of scratch lesions significantly as evidenced by the addition in interrupting strength of resutured scratch wound bespeaking that both ACE inhibitors have promoted collagenation significantly.
Both Capoten and enalapril intervention groups have significantly increased granulation tissue interrupting strength every bit good as dry weight as compared to those of vehicle treated control bespeaking enhanced fibroblast proliferation and collagen synthesis. The hydroxylation of proline and lysine is required for synthesis of collagen concatenation which provides strength and unity of all tissue fix cells ( Buffoni,1993 ) .The important addition in hydroxyproline content in the present survey indicates an addition in collagen content of the granulation tissue.The histopathological surveies revealed more sum of granulation tissue both in Capoten and Vasotec treated groups when compared with vehicle treated control group. These histological findings support the observation of increased dry weight, interrupting strength and hydroxyproline content in Capoten and Vasotec treated groups.It is rather clear from the present observations that both Capoten which contain sulfhydryl group and Vasotec incorporating carboxy alkyl group have important prohealing consequence on all facets of different lesion theoretical accounts. There is dearth of information in this respect.
The present survey does non uncover the exact mechanism of prohealing consequence of both ACE inhibitors. The initial event in lesion healing procedure is the inflammatory stage, which is due to the release of inflammatory go-betweens like bradykinin, prostaglandins and other factors. It has been reported that ACE inhibitors are known to increase bradykinin degrees by suppressing its dislocation ( Yang,1970 ) and straight or indirectly stimulate PGE2 synthesis ( Zusman,1981 ; Stephen,1982 ) . As mentioned earlier, bradykinin plays an of import function in bring oning redness by doing vasodilatation and hydrops is besides known to excite angiogenesis ( Hu and Fan,1993 ) and proliferation of fibroblasts by interacting with inflammatory cytokine interleukin-I ( Kimball and Fisher,1988 ) and tumour mortification factor – I ( Tiffany and Burch,1989 ) and bradykinin Acts of the Apostless as mitogen exciting DNA synthesis at that place by advancing cell proliferation ( Whitfield,1970 ; Owen and Villereal,1983 ) .As described earlier, kinins are known to excite release of histamine from mast cells which inturn stimulates proliferation of certain cells ( Cambel and Sgouris,1952 ; Butcher,1940 ) .The angiogenesis which is induced by bradykinin is an of import physiological procedure involved in lesion healing as it induces better nutritionary conditions for fibroblasts and cuticular cells to finally shut the lesion. NSAIDs ( Lee,1968 ; Francis and Marks,1977 ) and glucocorticoids ( Francis and Marks,1969 ) which inhibit PG synthesis and release, severally are known to stamp down wound mending proposing the cardinal function of PGs in lesion fix procedure.Therefore prohealing consequence of Capoten and Vasotec could be explained on the footing that these ACE inhibitors increase the bradykinin degree by forestalling its interruption down and increase prostaglandin degrees by exciting their synthesis and release.
They may move by exciting the release of histamine, as these autacoids are known to be involved in the procedure of lesion fix.
ACE inhibitors are the most appropriate antihypertensive drugs in patients with diabetes, nephropathy, left ventricular hypertrophy, congestive bosom failure, angina and station myocardial infarction instances. They are besides considered to be safe in patients enduring from asthma, diabetes mellitus and peripheral vascular disease. The present findings of the survey suggest that whenever these patients undergo surgery or sustain hurts the ACE inhibitors can advance wound healing.The findings of the present survey besides suggest that apart from the well established indicants of these ACE inhibitors they can besides be assuring drugs in advancing lesion healing, which is frequently a job in clinical pattern. However, farther clinical surveies in this respect are truly worthwhile.
Writer Contributions: Study construct and design: V.V.Gouripur, P.A.Patil. Acquisition of informations: Dr.S.
S.Torgal. Analysis and reading of informations: Dr.S.S.Torgal. Drafting of the manuscript: Dr.
Suneel.I.Majagi. Critical alteration of the manuscript for of import rational content: Dr.
Suneel.I.Majagi. Statistical analysis: Dr.A.
P.Hogade. Administrative, proficient or material support: Dr.S.
V.Hiremath. Study supervising: Dr.S.V.
The writers are thankful to Dr.
Reshma Davanageri, Associate Professor of Pathology for her counsel in histopathogical surveies.