Nitric oxide synthasis implication in indomethacin induced gastric mucosal lesion in albino rats: Immunohistochemical study

Eighty adult male albino rats weighing from 150-250 gm. were used in this study. They were divided into four groups: Group I [control group]: eight rats given distilled water 35 mg/kg subcutaneously. Group II [Indomethacin treated group]: twenty-four rats received indomethacin subcutaneously as a single dose of 35-mg/kg body. Group III [Indomethacin and L-NAME treated rats]: twenty-four rats received L-NAME [NG -nitro-L-arginine methyl ester] intraperitoneally at a dose of 50 mg/kg half an hour before giving the indomethacin intake. Group IV [Indomethacin and L-N treated rats]: twenty-four rats were given L-NIL [N6-[iminoethyl]-L-lysin] intraperitoneally at a dose of 3 mg/k half an hour before giving the indomethacin injection. At the assigned time [after 6, 24 48 and 72 hours], the animals were sacrificed. The stomach was removed. The specimens were processed for paraffin sections at 4 microns and stained by immunohistochemical staining for eNOS and iNOS. Immunohistochemically stained sections were submitted for the image analysis to detect the optical densities of immunoreactivity of eNOS and iNOS in the specimens of studied groups. Immunohistochemically-stained sections with eNOS of the control group revealed the presence of immunoreactivity in the form of brown deposits of variable intensities in blood vessels of the lamina propria and in the deep half of the gastric glands. Immunohistochemically-stained sections with iNOS of the control group revealed immunoreactivity mainly in the cells of the lamina propria and in cells of gastric glands especially at the bases of the glands. Expression of iNOS was less prominent than with eNOS in normal gastric mucosa. In indomethacin-administration rats immunohistochemically-stained sections with eNOS revealed that the level of expression of eNOS was significantly increased after ulcer induction reaching its maximum level at 24 hours then, declined then, started to increase again on the 72 hours group. Immunohistochemically-stained sections with iNOS revealed that there was increase in the level of expression of iNOS reaching its maximum on the 72 hours group. Expression of both iNOS and eNOS was significantly high on the third day Statistical results revealed that expression of iNOS was more than eNOS. In indomethacin and LNAME treated rats, immunohistochemically-stained sections with eNOS revealed decrease in eNOS immunoreactivity from 6 hours until 72 hours reaching its minimum level on the third day. It was also observed that expression of eNOS was less than that in indomethacin only administration group on the 24 and 72 hours but higher than the control. Immunohistochemically-stained sections with iNOS revealed increase in iNOS immunoreactivity from 6 hours until 72 hours reaching its maximum level on the third day. Expression of iNOS was more than that in indomethacin given group or control group. It was observed that iNOS immunoreactivity was higher than eNOS immunoreactivity in this group. In indomethacin and L NIL treated rats, immunohistochemically-stained sections with eNOS revealed increase in eNOS immunoreactivity reaching its maximum level on 48 hours and 72 hours as compared with animals received indomethacin only or received indomethacin and L-NAME Immunohistochemically-stained sections with iNOS revealed decrease in iNOS immunoreactivity reaching its minimum level on the third day as compared with indomethacin and L-NAME given group but higher than the control group, also expression of iNOS was more in 6, 24, 48 hours groups but less in 72 hours group as compared with indomethacin only given group. The eNOS immunoreactivity was higher than iNOS immunoreactivity in this group. The present data suggested that eNOS-derived NO is the most important in terms of affects on the healing process, most likely through its effects on angiogenesis. It could be concluded that inhibition of NOS could have either beneficial or deleterious effects on gastric injury, depending on which isoforrn is being inhibited

role of Nitric Oxide synthases inhibitors in indomethacin induced gastric mucosal lesion in albino rat

The present work was undertaken to explore the role of nitric oxide synthases [NOSs] inhibitors L-NAME [non-selective constitutive NOS and inducible NOS inhibitor] and L-NIL [selective inducible NOS inhibitor] in the pathogenesis of indomethacin induced gastric mucosal lesions in the early stage of ulcer development and healing [0-3 days]. Eighty adult male albino rats weighing from 150-250 gm. were used in this study. They were divided into four groups: Group I [control group]: eight rats given distilled water 35 mg/kg subcutaneously. Group II [Indomethacin treated group]: twenty-four rats received indomethacin subcutaneously as a single dose of 35-mg/kg body. Group III [Indomethacin and L-NAME treated rats]: twenty-four rats received L-Name [NG initro-L-arginine methyl ester] intraperitoneally at a dose of 50 mg/kg half an hour before giving the indomethacin Group IV [Indomethacin and L-NIL treated rats]: twenty-four rats were given L-NIL [N6- [iminoethyl]-L-lysine] intraperitoneally at a dose of 3 mg/kg half an hour before giving the indomethacin. At the assigned time [after 6 hours, 24 hours, 48 hours and 72 hours] the animals were sacrificed. The stomach was removed and dissected along the greater curvature. The macroscopic lesions in obtained specimens were assessed by magnifying lens and dissecting microscope The numerical data obtained from macroscopic studies of stomach sections were statistically analyzed to obtain the mean ulcer index. The specimens were processed for paraffin sections at 6 microns and stained by haematoxylin and eosin stain; and examined histologically. In the control group, macroscopic and histological examination revealed normal appearance of the gastric mucosa. In indomethacin-administrated group, macroscopic and histological examination revealed time-dependent occurrence of damage in the stomach from 6 hours up to 72 hours reaching maximum damage at 72 hours. After 72 hours, there was evidence of healing process. In indomethacin and L-NAME administrated group, it was observed that pre-treatment with L-NAME significantly enhanced gastric mucosal lesions induced by indomethacin. Macroscopic and histologieal examination revealed significant increase in the mean ulcer index in the mucosa of the stomach as compared with indomethacin only given rats reaching its maximum effect on the third day. No or little evidence of regenerating epithelium on the third day was observed. In indomethacin and L-NIL administrated group, it was observed that pre-treatment with L-NIL significantly reduced but not prevented gastric mucosal lesions induced by indomethacin. Macroscopic and histological examination revealed time-dependent occurrence of damage in the stomach from 6 hours up to 48 hours reaching maximum damage at 48 hours then ulcer index began to decrease on 72 hours. There was decrease in the mean ulcer index as compared with rats given either indomethacin and L-NAME or indomethacin only. Evidence of healing was observed in 48 hours and 72 hours groups. The results of the present study confirmed the importance of NOS inhibitors in the modulation of gastric ulcer healing in early stage of ulcer development [0-3] days. The present data suggested that eNOS-derived NO is the most important in terms of effects on the healing process, most likely through its effects on angiogenesis

Effect of preganglionic parasympathetic denervation on Nitric Oxide synthase in submandibular gland of adult albino rat

Adult albino rats were subjected to chorda tympani neurectomy on the right side and the left side served as the control. After different survival periods, the control and experimental submandibular glands were discected out and processed for histological and histochemical examinations. Chorda tympani neurectomy resulted in atrophic changes in about 90% of both seromucous acini and granular convoluted tubules of the submandibular gland. They showed statistically significant reduction in their mean diameters after denevation. The reduction in the diameter of the acini was more marked than that of the tubules. The atrophic acini became separated by wide spaces and their cells showed cytoplasmic vacuolation two weeks after chorda tympani neurectomy. At the third and the fourth weeks, an insignificant increase in the diameter was noticed in the tubules and acini. The interlobular striated ducts showed cytoplasmic vacuolation two weeks after denervation which became more prominent during the third and fourth week after chorda tympani neurectomy. After denervation, NADPH-d positive nerve terminals were absent around the majority of acini and the granular convoluted tubules and were seen around the remaining 7-10% of the acini and 10-23% of the tubules. Throughout the period of denervation, NADPH-d positive nerve terminals were found around the striated ducts, the interlobular ducts and the blood vessels. The majority of the NADPH-d positive nerve terminals around the acini and granular convoluted tubules are parasympathetic in origin derived from the chorda tympani. The origin of NADPH-d positive nerve fibers around some acini and granular convoluted tubules and in relation to the remaining duct system and blood vessels needs further investigation

Prenatal development of the human parotid gland

The prenatal development of the human parotid gland has been investigated in 26 fetuses from the 10th week of gestation to full term. At 10-12 weeks, the gland was composed of primitive ducts and terminal buds of primitive acini surrounded by loose mesenchyme. The acini continued to increase in number and size till full term. At 16 weeks, the lobulation of the developing gland was recognizable together with differentiation of the primitive ducts into intra- and interlobular ducts. At 20 weeks, both intercalated and striated ducts were distinguished and their number increased gradually with age. At birth, the ducts and acini appeared fewer and less crowded than those of the adult and the gland appeared devoid of fat cells. PAS- and AB-positive secretory materials appeared in the epithelial cells of both ducts and acini and in their lumina during the 12th week. This secretory activity persisted throughout pregnancy. The functional significance of the secretory products is discussed