protective effect of L-tryptophan versus alpha lipoic acid against L-arginine-induced experimental acute pancreatitis in albino rats

This study was conducted to investigate the possible protective effects of L- treptophan "a precursor of melatonin" and alpha lipoic acid against L- arginine-induced experimental acute pancreatitis in albino rats. Fourty adult male albino rats [200- 250g] were randomized into 4 groups [n= 10]. Group I, the control group was given 0.9% saline intraperitoneally [i.p]. Group II, was given 500 mg/lOOg L-arginine [i.p] as a single dose to induce acute pancreatitis. Group III: was given 250mg/kg L-tiyptophan [i.p] 30 mm prior to L- arginine injection. Group IV: was given 50mg/kg alpha lipioc acid [i.p] 30 mm prior to L-arginine. Before scarifice, blood samples were obtained from all groups to assay serum amylase and interleukin 6. Animals were sacrificed after 6 hours. For the histopathological study, pancreatic tissue was prepared for histological [H and E, PAS] histochemical [Tween stain for lipases] and immunohistoehemical [Bax stain for apoptosis] techniques. Both qualitative and quantitative analyses were done to assess the degree of acinar cells affection. It was revealed that serum amylase and interleukin 6 in group II rose rapidly. Microscopically, severe acinar cells degeneration, interstitial edema, diffuse bleeding and inflammatory infiltration were demonstrated. These changes were markedly improved with the administration of both L- tryptophan and alpha lipoic acid. It was concluded that both L- tryptophan and alpha lipoic acid reduced the effects of L-arginine-induced acute pancreatitis with better protection achieved by L-tryptophan administration

Light and electron microscopic study on the protective role of corneal epithelium against the effect of "UVB" radiation on rabbit cornea

The human eye might be subjected to repeated exposure to ultraviolet radiation [UVR] either during a single day or over a longer period of time. It is known that the cortical epithelium strongly absorbs UVR. The aim of this study was to evaluate the protective role of corneal epithelium against the effect of UVB radiation on corneas of albino rabbits in comparison with that on de-epithelialized corneas. Sixteen adult female New Zealand albino rabbits [3-3.5 Kg] were divided into 4 groups, 4 rabbits each. Group I served as control. Group II served also as control, but their corneas underwent manual de-. In group III, corneas were exposed to UVB irradiation, peaked at 3l2nm as a single dose [3.12J/cm2] for 30 minutes. In group IV corneas underwent manual de-epithelialization. 5 minutes prior to UVB exposure. All animals were sacrificed after 48 hours, and the corneas were removed and processed for histological and transmission electron microscopic study. The histological results of group III revealed that the corneas had slight edema and the keratocytes in the outer stroma appeared to be affected. Ultrastructural evaluation of this group showed affected epithelial cells and the keratocytes revealed early apoptotic changes like chromatin condensation. Results of group IV showed that the stromal damage was deeper and more extensive. The keratocytes had been markedly affected in the entire thickness and there was thinning out of Descemet's membrane. Ultrastructurally, the keratocytes showed chromatin condensation, fragmentation and cell shrinkage. Disorganized collagen lamellae were also seen. It was concluded that the removal of the corneal epithelium makes the underlying ocular structures-more susceptible to damage by UVB in the 312nm range. Further studies are needed to investigate whether the corneal epithelium has protective properties against UVB at other wavelengths

Light and electron microscopic study on the possible protective effect of taurine against thioacetamide induced liver damage in albino rats

Thioacetamide [TAA] is used as a fungicide and one of the human carcinogens which induces multiorgan failure including hepatotoxicity. The aim of this study was to evaluate the protective effect of taurine [2- amino-ethane sulfonic acid], against [TAA] induced hepatotoxicity in albino rats. Twenty adult male albino rats [150-200g] were divided into 4 groups, 5 rats each. Group I served as control, received [1ml/100g] 0.9% saline intraperitoneally [i p] for 4 days. Group II received [TAA] [300mg/kg] [i.p] for two consecutive days. Group III received taurine [400mg/kg] [i.p] for two consecutive days prior to the [TAA]. Group IV received the same dose of taurine only. All animals were sacrificed on the 5th day after the beginning of the experiment. For histological studies, liver sections were stained with H and E, PAS and Masson's trichrome stains. Other minute specimens from the liver were processed for transmission electron microscopic study. The histological results of [TAA] injected rats revealed loss of normal hepatic architecture, most of the hepatocytes of centrilobular region showed necrosis and vacuolated cytoplasm,, marked decrease of PAS positive material and minimal increase of collagen fibers inbetween blood sinusoids were noticed. The ultrastructural findings showed that hepatocytes contained polymorphic mitochondria with apparent loss of their cristea, numerous cytoplasmic vacuoles, loss of short microvilli and apparent decrease of the glycogen granules.These changes were improved markedly, both histologically and ultrastructurally with taurine administration. It is concluded that [TAA] induces severe hepatic alterations. These alterations were less prominent in animals treated with taurine indicating that taurine can be used as a possible hepatoprotector agent against [TAA] induced toxicity

protective effects of vitamin E versus vitamin C against cisplatin ototoxicity in guinea pigs [histological and audiological study]

The protective effects of both vitamin E and C against cisplatin induced ototoxicity were assessed histologically and audiogically. This was done by quantifying the extent of cochlear damage with the light microscope, scanning electron microscope and with measurement of the Distortion Product Otoacoustic Emissions [DPOAEs]. Twenty-five adult male guinea pigs were used in this study. They were divided into control group, cisplatin group that was injected 8 mg/kg cisplatin intra-peritoneally [i.p.], vitamin E group that was injected 500 mg/kg of vitamin E i.p.30 mm prior to cisplatin injection, and vitamin C group which was given 200 mg/kg of vitamin C i.p. 30 min before cisplatin administration. When administered alone, cisplatin induced loss and vacuolation of outer hair cells [OHCs] as seen by LM examination. Scanning EM revealed fusion, disarrangement and loss of some stereocilia in the remaining OHCs especially in the basal turn. In contrast, inner hair cells resisted cisplatin ototoxicity. Audiological assessment demonstrated reduction in DPOAEs amplitudes and S/N values in all frequencies. Both vitamin E and C reduced cisplatin ototoxicity, with better protection achieved by vitamin C administration. Scanning EM examination showed that OHCs were similar to the control configuration after vitamin C administration while after protection with vitamin E, OHCs of the third row showed fusion and absorption of the stereocilia in some parts. In addition, both DPOAEs amplitudes and S/N ratio were near the control values up to 4 KHz. However, above 4 KHz both vitamins failed to achieve the full protection, with vitamin C showing better performance in these high frequencies. We conclude that both vitamins had protective effects against cisplatin induced ototoxicity, with vitamin C inducing more protection in the used regimen