- Email: [email protected]
Serial endoscopic observation of the effects of histamine, aspirin, steroids, and alcohol on standardized gastric ulcers in dogs
S6
Serial endoscopic observation of the effects of histamine, aspirin, steroids, and alcohol on standardized gastric ulcers in dogs Choichi Sugawa, M.D. Charles E. Lucas, M.D. Alexander J. Walt, M.D. Detroit, Michigan Acute gastric ulcers were made in the body and antrum of dogs by a transserosal intramural injection of dilute acetic acid and then observed by serial gastroscopy and photography until postmortem examination at 3 or 6 weeks. Standardized ulcer healing of this model was identified in a control group and then compared to 4 medication groups receiving systemic histamine, aspirin, steroids or alcohol. Ulcer healing was delayed in both the antrum and the body of the stomach by histamine, steroids, and alcohol, but only in the body of the stomach by aspirin. Superficial mucosal erosions usually accompanied delay in ulcer healing in all groups. Although wide-spread utilization of the fiberoptic gastroscope has permitted significant advances clinically in the identification and subsequent observation of gastric ulcers, little application of this instrument has been made in the study of experimental gastric disease. The present study was designed to evaluate the role of serial gastroscopy and photography as a means of studying (1) the healing processes of standardized ulcers in the antrum and body of the stomach in the living dog, and (2) the effects of selected medications upon this healing. The standardized ulcer model selected was the acetic acid ulcer originally described by Takagi' in rats and modified in this laboratory in dogs.' This model is made by a transserosal injection of dilute acetic acid, thus circumventing the need for a gastrotomy and permitting early gastroscopy. METHODS Acetic Acid Ulcer Model: The ulcers were produced during laparotomy under general anesthesia by the intramural injection through a 26-gauge needle of 0.5 ml 40% acetic acid into the anterior wall of both the antrum and body of the stomach. In order to facilitate subsequent gastroscopic observations, the antral injection was made 7 cm proximal to the pylorus and 1 cm from the greater curvature, whereas the injection in the gastric body was made 3 cm proximal and to the left of the incisura angularis. The total operative procedure required
about 30 minutes and has been performed in over 75 dogs without a death. The ulcers grew to maximal size at about one week (Figure 1) averaging 154 in ulcer index (UI = length x width in mm) and penetrating to the serosa. The ulcer index averaged 20 by 3 weeks and 0 by 6 weeks. No differences in healing could be seen between antral and body ulcers. The ulcer base which consisted of a deep layer of granulation tissue and a superficial layer of necrotic debris at 1 week became smaller and contained more mature granulation tissue at 3 weeks. The base was completely covered by regenerated mucosa within 6 weeks. Gastroscopic Technique: Gastroscopy with an Olympus GTF-A was most easily performed in dogs weighing 15 to 20 kg and has been successfully carried out over 250 times without a death. The dogs were allowed only liquids by mouth for 15 hours prior to examination at which time they were anesthetized with intravenous pentobarbital using 28.5 mg/kg body weight. The gastroscope was inserted through a special wooden mouth plate measuring 15 x 7 cm and containing a 4 x 7 cm central hole to prevent biting and injury to the fiberoptic bundle. With the dog in either the supine or lateral positions, the instrument was passed along the midline of the posterior pharyngeal wall while gentle traction was exerted on the tongue. Little or no resistance was encountered until the cardioesophageal junction was
From the Robert S. Marx Surgical Laboratories, Department of Surgery, Wayne State University School of Medicine, 1400 Chrysler Freeway, Detroit, Michigan, and Detroit General Hospital. Reprint requests: Alexander ). Walt, M.D., Department of Surgery, Wayne State University School of Medicine, 1400 Chrysler Freeway, Detroit, Michigan.
GASTROINTESTINAL ENDOSCOPY
57
the dogs in the left lateral position. The pylorus was best seen at 80 cm in the 12 o'clock position at variable angles (Figure 2 a). Tilting the head of the table downward 30 0 permitted better pyloric visualization on occasion. Following this, a tangential view of the lesser curvature and cardia was best obtained by bending the camera tip sharply upward ("ur). Finally, the greater curvature, fundus and cardia were best seen by using the retroflexion maneuver (U-turn method) with the instrument inserted approximately 80 cm (Figure 2 b) and the camera pointed in the 6 o'clock direction with a "ur angle.
Figure 1: Antral ulcer one week following operation. Note ellipsoid crater with marginal swelling.
reached at which time intermittent insufflation and gentle continuous pressure facilitated passage into the stomach. The instrument could then be readily advanced to the angularis at approximately 60 cm from the incisors. The angularis was best visualized at the 12 o'clock position at an angle of "N" or "0" on the gastroscope with the dogs in the supine or right lateral position. The ulcers in the body were best visualized at about 55 to 60 cm from the incisors in the 10 o'clock direction and at an angle "U2" with the dogs in the right lateral position. Alternatively, with the dog in the supine position, the ulcer was best seen 60 to 65 cm from the incisors in the 10 o'clock direction and at a "U3" angle. The "u" angle was recorded as "U1," "U2," or "U3" reflecting small, moderate, and marked degrees respectively. Antral ulcers were situated at approximately 75 cm in the 12 o'clock direction and an angle of "U2" with the dogs supine or at 65 cm in the 12 o'clock direction and an angle of "U2" with
Figure 2: Pylorus as best seen in the 12 o'clock direction at 80 cm, a; Retroflexion maneuver or U-turn method facilitating visualization of greater curvature, fundus and cardia, b.
VOLUME 18, NO.2, 1971
Experimental Protocol: Experimental gastric ulcers were created in both the body and antrum of 52 dogs using the acetic acid technique described above. Gastroscopy with gastric photography was performed 1 hour after operation in 12 dogs, at 2 days in 12 dogs, at 5 days in 12 dogs, and at 1 week and weekly thereafter in all dogs until postmortem examination at either 3 or 6 weeks. Three dogs died of perforation of the ulcer during the first week, and the remaining 49 dogs were divided at 1 week into 5 groups: (1) control group with no medication-13 dogs of whom 4 were sacrificed at 1 week to serve as a baseline; (2) histamine group-9 dogs receiving a daily instrmuscular injection of 2 mg/kg body weight of histamine in beeswax; (3) aspirin group-9 dogs receiving an oral daily dose of 120 mg/kg body weight of commercial crystalline aspirin diluted into 500 ml drinking water and given twice daily; (4) steroid group-9 dogs receiving a daily subcutaneous injection of 62.5 mg Solumedrol®; (5) alcohol group-9 dogs receiving 10% alcohol in water orally in the amount of 500 ml twice daily. Gross photography and measurements were obtained at postmortem examination which was performed immediately after the last gastroscopic examination. Hematoxylin and eosin and periodic acid-Schiff (PAS) stains were made for subsequent histology. Ulcer size throughout the study was recorded as ulcer index.
58
BODY
ANTRUM 160
160
140
140
120
120
_1
100
...E E
80
80
60
60
40
40
><
...
11:1
Z
•...
..
u
Figure 3: Rate of ulcer healing in the 5 groups. Antral ulcer healing (left) was delayed by histamine, steroids, and alcohol. Ulcer healing in the gastric body (right) was delayed in all 4 medication groups.
:)
20
20
23456 TIME
IN
WEEKS
1234 FOLLOWING
RESULTS The gastroscopic estimate of ulcer size immediately prior to postmortem examination correlated with autopsy measurements to within an average of 1 mm. The autopsy measurements were slightly smaller, probably reflecting the insufflation during gastroscopy. The rate of control ulcer healing and the retarding effect of selected medications are summarized in Figure 3. Whereas all control ulcers had healed by 6 weeks, antral ulcer healing was delayed at 3 and 6 weeks in the histamine and steroid groups, and at 3 weeks in the alcohol group. Healing of ulcers in the body was impaired throughout the study period in the histamine, steroid, and aspirin groups, and at 3 weeks in the alcohol group. Diffuse mucosal erosions accompanied delayed ulcer healing and were more pronounced in both the antrum and body of the histamine and steroid groups and in the body of the aspirin group (Table I). No erosions developed in the control group. The histologic pattern of healing in the 4 medication groups and the control group was identical except for rate and has previously been described.' The degree of mucosal PAS staining in general correlated directly with the degree of ulcer healing except in the alcohol group where the ulcer healing occurred despite insignificant mucosal PAS uptake (Figure 4, Table I). DISCUSSION The technique of gastric ulcer production with an intramural injection of dilute acetic acid and the subsequent study thereof by serial gastroscopy provides an excellent model for studying the effects of selected medications upon ulcer healing. Serial endoscopy is well tolerated and simultaneous photography provides a precise means of objectively evaluating the degree of ulcer
5
6_
SURGERY
healing and size as evidenced by the extremely close correlation with postmortem measurements. The techniques described herein provide a practical means of testi ng both the beneficial and deleterious effects of selected medications on the rate of healing of experimental gastric ulcers. Table I.
Mucosal Erosions And PAS Uptake Antrum Groups Erosions PAS Uptake* Control None 2.8 Histamine Marked 0.5 Aspirin None 2.6 Steroids Moderate 0.9 Alcohol Minimum** 1.3 *PAS Uptake Code: O-none, 3=normal
Body Erosions PAS Uptake None 2.8 Moderate 0.5 Moderate 1.4 Moderate 0.8 Minimum 1.0
"Minimum -several areas of redness without distinct border
The fact that various medications affect ulcers in the antrum and body differently points out the essential need to describe the exact location of experimental ulcers. The mechanism for the different rates of healing between the antrum and body of the stomach when exposed to different medications is not apparent and warrants further evaluation. In most instances, however, delay in ulcer healing correlates directly with a decrease in PAS mucosal staining, reflecting an associated mucin deficiency. It is obvious, however, that a number of other factors may be involved. REFERENCES 1. TAKAGI K, OKABE 5, SAZIKI R: A new method for production of chronic gastric ulcer in rats and the effect of several drugs on i1s healing. lap I Pharmacal, 19:418, 1969 2. SUGAWA C, LUCAS C E, WALT A J: Effect of histamine and aspirin on healing of standardized gastric ulcers in dogs. Surg, in press
GASTROINTESTINAL ENDOSCOPY
Serial endoscopic observation of the effects of histamine, aspirin, steroids, and alcohol on standardized gastric ulcers in dogs Choichi Sugawa, M.D. Charles E. Lucas, M.D. Alexander J. Walt, M.D. Detroit, Michigan Acute gastric ulcers were made in the body and antrum of dogs by a transserosal intramural injection of dilute acetic acid and then observed by serial gastroscopy and photography until postmortem examination at 3 or 6 weeks. Standardized ulcer healing of this model was identified in a control group and then compared to 4 medication groups receiving systemic histamine, aspirin, steroids or alcohol. Ulcer healing was delayed in both the antrum and the body of the stomach by histamine, steroids, and alcohol, but only in the body of the stomach by aspirin. Superficial mucosal erosions usually accompanied delay in ulcer healing in all groups. Although wide-spread utilization of the fiberoptic gastroscope has permitted significant advances clinically in the identification and subsequent observation of gastric ulcers, little application of this instrument has been made in the study of experimental gastric disease. The present study was designed to evaluate the role of serial gastroscopy and photography as a means of studying (1) the healing processes of standardized ulcers in the antrum and body of the stomach in the living dog, and (2) the effects of selected medications upon this healing. The standardized ulcer model selected was the acetic acid ulcer originally described by Takagi' in rats and modified in this laboratory in dogs.' This model is made by a transserosal injection of dilute acetic acid, thus circumventing the need for a gastrotomy and permitting early gastroscopy. METHODS Acetic Acid Ulcer Model: The ulcers were produced during laparotomy under general anesthesia by the intramural injection through a 26-gauge needle of 0.5 ml 40% acetic acid into the anterior wall of both the antrum and body of the stomach. In order to facilitate subsequent gastroscopic observations, the antral injection was made 7 cm proximal to the pylorus and 1 cm from the greater curvature, whereas the injection in the gastric body was made 3 cm proximal and to the left of the incisura angularis. The total operative procedure required
about 30 minutes and has been performed in over 75 dogs without a death. The ulcers grew to maximal size at about one week (Figure 1) averaging 154 in ulcer index (UI = length x width in mm) and penetrating to the serosa. The ulcer index averaged 20 by 3 weeks and 0 by 6 weeks. No differences in healing could be seen between antral and body ulcers. The ulcer base which consisted of a deep layer of granulation tissue and a superficial layer of necrotic debris at 1 week became smaller and contained more mature granulation tissue at 3 weeks. The base was completely covered by regenerated mucosa within 6 weeks. Gastroscopic Technique: Gastroscopy with an Olympus GTF-A was most easily performed in dogs weighing 15 to 20 kg and has been successfully carried out over 250 times without a death. The dogs were allowed only liquids by mouth for 15 hours prior to examination at which time they were anesthetized with intravenous pentobarbital using 28.5 mg/kg body weight. The gastroscope was inserted through a special wooden mouth plate measuring 15 x 7 cm and containing a 4 x 7 cm central hole to prevent biting and injury to the fiberoptic bundle. With the dog in either the supine or lateral positions, the instrument was passed along the midline of the posterior pharyngeal wall while gentle traction was exerted on the tongue. Little or no resistance was encountered until the cardioesophageal junction was
From the Robert S. Marx Surgical Laboratories, Department of Surgery, Wayne State University School of Medicine, 1400 Chrysler Freeway, Detroit, Michigan, and Detroit General Hospital. Reprint requests: Alexander ). Walt, M.D., Department of Surgery, Wayne State University School of Medicine, 1400 Chrysler Freeway, Detroit, Michigan.
GASTROINTESTINAL ENDOSCOPY
57
the dogs in the left lateral position. The pylorus was best seen at 80 cm in the 12 o'clock position at variable angles (Figure 2 a). Tilting the head of the table downward 30 0 permitted better pyloric visualization on occasion. Following this, a tangential view of the lesser curvature and cardia was best obtained by bending the camera tip sharply upward ("ur). Finally, the greater curvature, fundus and cardia were best seen by using the retroflexion maneuver (U-turn method) with the instrument inserted approximately 80 cm (Figure 2 b) and the camera pointed in the 6 o'clock direction with a "ur angle.
Figure 1: Antral ulcer one week following operation. Note ellipsoid crater with marginal swelling.
reached at which time intermittent insufflation and gentle continuous pressure facilitated passage into the stomach. The instrument could then be readily advanced to the angularis at approximately 60 cm from the incisors. The angularis was best visualized at the 12 o'clock position at an angle of "N" or "0" on the gastroscope with the dogs in the supine or right lateral position. The ulcers in the body were best visualized at about 55 to 60 cm from the incisors in the 10 o'clock direction and at an angle "U2" with the dogs in the right lateral position. Alternatively, with the dog in the supine position, the ulcer was best seen 60 to 65 cm from the incisors in the 10 o'clock direction and at a "U3" angle. The "u" angle was recorded as "U1," "U2," or "U3" reflecting small, moderate, and marked degrees respectively. Antral ulcers were situated at approximately 75 cm in the 12 o'clock direction and an angle of "U2" with the dogs supine or at 65 cm in the 12 o'clock direction and an angle of "U2" with
Figure 2: Pylorus as best seen in the 12 o'clock direction at 80 cm, a; Retroflexion maneuver or U-turn method facilitating visualization of greater curvature, fundus and cardia, b.
VOLUME 18, NO.2, 1971
Experimental Protocol: Experimental gastric ulcers were created in both the body and antrum of 52 dogs using the acetic acid technique described above. Gastroscopy with gastric photography was performed 1 hour after operation in 12 dogs, at 2 days in 12 dogs, at 5 days in 12 dogs, and at 1 week and weekly thereafter in all dogs until postmortem examination at either 3 or 6 weeks. Three dogs died of perforation of the ulcer during the first week, and the remaining 49 dogs were divided at 1 week into 5 groups: (1) control group with no medication-13 dogs of whom 4 were sacrificed at 1 week to serve as a baseline; (2) histamine group-9 dogs receiving a daily instrmuscular injection of 2 mg/kg body weight of histamine in beeswax; (3) aspirin group-9 dogs receiving an oral daily dose of 120 mg/kg body weight of commercial crystalline aspirin diluted into 500 ml drinking water and given twice daily; (4) steroid group-9 dogs receiving a daily subcutaneous injection of 62.5 mg Solumedrol®; (5) alcohol group-9 dogs receiving 10% alcohol in water orally in the amount of 500 ml twice daily. Gross photography and measurements were obtained at postmortem examination which was performed immediately after the last gastroscopic examination. Hematoxylin and eosin and periodic acid-Schiff (PAS) stains were made for subsequent histology. Ulcer size throughout the study was recorded as ulcer index.
58
BODY
ANTRUM 160
160
140
140
120
120
_1
100
...E E
80
80
60
60
40
40
><
...
11:1
Z
•...
..
u
Figure 3: Rate of ulcer healing in the 5 groups. Antral ulcer healing (left) was delayed by histamine, steroids, and alcohol. Ulcer healing in the gastric body (right) was delayed in all 4 medication groups.
:)
20
20
23456 TIME
IN
WEEKS
1234 FOLLOWING
RESULTS The gastroscopic estimate of ulcer size immediately prior to postmortem examination correlated with autopsy measurements to within an average of 1 mm. The autopsy measurements were slightly smaller, probably reflecting the insufflation during gastroscopy. The rate of control ulcer healing and the retarding effect of selected medications are summarized in Figure 3. Whereas all control ulcers had healed by 6 weeks, antral ulcer healing was delayed at 3 and 6 weeks in the histamine and steroid groups, and at 3 weeks in the alcohol group. Healing of ulcers in the body was impaired throughout the study period in the histamine, steroid, and aspirin groups, and at 3 weeks in the alcohol group. Diffuse mucosal erosions accompanied delayed ulcer healing and were more pronounced in both the antrum and body of the histamine and steroid groups and in the body of the aspirin group (Table I). No erosions developed in the control group. The histologic pattern of healing in the 4 medication groups and the control group was identical except for rate and has previously been described.' The degree of mucosal PAS staining in general correlated directly with the degree of ulcer healing except in the alcohol group where the ulcer healing occurred despite insignificant mucosal PAS uptake (Figure 4, Table I). DISCUSSION The technique of gastric ulcer production with an intramural injection of dilute acetic acid and the subsequent study thereof by serial gastroscopy provides an excellent model for studying the effects of selected medications upon ulcer healing. Serial endoscopy is well tolerated and simultaneous photography provides a precise means of objectively evaluating the degree of ulcer
5
6_
SURGERY
healing and size as evidenced by the extremely close correlation with postmortem measurements. The techniques described herein provide a practical means of testi ng both the beneficial and deleterious effects of selected medications on the rate of healing of experimental gastric ulcers. Table I.
Mucosal Erosions And PAS Uptake Antrum Groups Erosions PAS Uptake* Control None 2.8 Histamine Marked 0.5 Aspirin None 2.6 Steroids Moderate 0.9 Alcohol Minimum** 1.3 *PAS Uptake Code: O-none, 3=normal
Body Erosions PAS Uptake None 2.8 Moderate 0.5 Moderate 1.4 Moderate 0.8 Minimum 1.0
"Minimum -several areas of redness without distinct border
The fact that various medications affect ulcers in the antrum and body differently points out the essential need to describe the exact location of experimental ulcers. The mechanism for the different rates of healing between the antrum and body of the stomach when exposed to different medications is not apparent and warrants further evaluation. In most instances, however, delay in ulcer healing correlates directly with a decrease in PAS mucosal staining, reflecting an associated mucin deficiency. It is obvious, however, that a number of other factors may be involved. REFERENCES 1. TAKAGI K, OKABE 5, SAZIKI R: A new method for production of chronic gastric ulcer in rats and the effect of several drugs on i1s healing. lap I Pharmacal, 19:418, 1969 2. SUGAWA C, LUCAS C E, WALT A J: Effect of histamine and aspirin on healing of standardized gastric ulcers in dogs. Surg, in press
GASTROINTESTINAL ENDOSCOPY