Physiological parameters
Non-significant changes in rectal temperature, heart rate and respiratory rate were noticed throughout the observation period after contrast administration in animals of group I and II (Fig 1, 2, 3) and the mean values remained within the normal physiological range. There was marginal non-significant increase in heart rate and respiratory rate at 1 hour following administration of contrast agents in both the groups and there after returned near normalcy at 24 hour interval. Similar observations had been observed by
Sharma et al., (2015) and
Gowtham, (2017) after administration of contrast agents in dogs. On the other hand,
Ganesh, (1995) recorded decrease in temperature after 5 minutes of iohexol @ 1000 mgI/kg administration which might be due to effect of contrast media on the pyelo motor mechanism. Iohexol causes tachycardia which could be attributed to generalized vasodilatation and subsequent hypotension involving reflex tachycardia as reported by
Ganesh, (1995) and also documented that sodium diatrizoate caused bradycardia at 5 minutes after administration due to the presence of sodium cations in urografin 76% and its effect was reversed after 30 minutes following injection of dye. Marginal increase in respiration rate after 5 minutes of administration of both sodium diatrizoate (600 mgI/kg;1000 mgI/kg) and iohexol (600 mg I/kg;1000 mgI/kg) contrast media might be due to iodine particles present in the contrast media which had influenced the hypothalamic reaction and chemoreceptor of respiratory centre resulting in increased respiratory rate (
Ganesh, 1995).
Haematological parameters
In animals of group I and II, mean haemoglobin, packed cell volume (%), total erythrocyte count (TEC) and TLC showed non-significant decrease at 1 hr following a marginal increase up to 24 hr (Table 1) However, these values remained within normal physiological range in both the groups. There was non-significant reduction in haemoglobin value in both groups which might be due to hypervolaemia caused by haemodilution by contrast administration. This resulted in fluid shift from extravascular to intravascular compartments within a short period after the administration (
Ganesh, 1995). The decrease in PCV might be attributed to haemodilution produced by both contrast agents. Haemoglobin, Packed cell volume (PCV %), TEC and TLC values showed non-significant difference between groups at various time intervals. To its contrary,
Sharma et al., (2015) observed significant (p<0.05) decline in mean haemolglobin, packed cell volume and TEC at 1 hr after urografin administration. Intravenous administration of contrast agents produced transient hypervolemia because water was rapidly transported from the extravascular compartment to the circulation and caused marked fall in haematocrit
(Sharma et al., 2015). The non-significant decrease in TEC and TLC might be due to more fluid in the blood volume caused by the shift of fluid from the extravascular to intravascular compartments after contrast administration. Similar pattern of non-significant decrease in TEC was seen in group II which resulted due to increase in plasma osmolality because of intravenous injection of ionic contrast agents which was five to eight times hypertonic than that of normal body fluid. This caused water to leave the erythrocytes and enter the plasma resulting in shrinkage and deformity of the erythrocytes. These findings were in accordance with
Koe and Alkan, (2002) who recorded non-significant (p>0.05) changes in white blood counts in ionic (urografin 76%) and non-ionic (Iopromide) groups 1 hr after injection of media contrast. Similar finding was reported by
Gowtham, (2017) after iohexol administration at a dose rate of 800 mgI/kg body weight in both male and female dogs.
Neutrophil, lymphocyte and monocyte count showed non-significant decrease at 1 hr in group I and II, which further increased non-significantly at 6 hr and 24 hr following contrast administration and values remains within normal physiological range. Similar observation was reported by
Sharma et al., (2015) after iohexol @ 600 mgI/kg body weight and
Gowtham, (2017) after iohexol administration @ 800 mgI/ kg body weight. In contrary to our study,
Sharma et al., (2015) reported a significant (p<0.05) decline in neutrophils at 1 hr after administration of urografin @ 600 mgI/kg body weight and then a gradual increase in the values was noted. This could be attributed to iodinated contrast agent which increased constitutive and inflammatory neutrophils apoptosis over a period and concentration dependent manner in vitro with ionic contrast media appearing to have a more toxic effect
(Fanning et al., 2002). Non-significant decrease in neutrophils was recorded at 1 hr in both the groups which might be due to anaphylactic reaction against contrast agents of both iohexol and urografin. The anaphylaxis reaction resulting due to administration of contrast agent occurred as neutropenia by means of neutrophils sequestration causing a rapid shift to the margin pool. This neutropenia was thought to be the primary cause of the change in the total leucocyte counts
(Sharma et al., 2015). Present study revealed a non-significant decrease in eosinophils count at 1 hr in group I which might be due to administration of antihistaminic prior to administration of iohexol. Whereas, animals of group II showed non-significant increase from base value till 24 hr of observation period after urografin administration but the values remained within normal physiological limits. However,
Sharma et al., (2015) documented a significant (p<0.05) decrease in eosinophils at 1 hr after injection of iohexol @ 600 mgI/kg and urografin @ 600 mgI/kg body weight in dogs and values gradually increased non-significantly upto 24 hr in both goups. Basophils were not found in group I and II during study period. The observation simulated with the finding of
Gowtham, (2017) following iohexol administration @ 800 mgI/kg body weight in both male and female dogs.
Biochemical parameters
The serum glucose levels fluctuated within normal physiological range without any significant difference within group and between groups at various time intervals (Table 2). Serum glucose levels showed non-significant increase at 1 hr in group I and II after contrast agent administration with a decrease at 6 hr interval thereafter returning to near normalcy at 24 hr of observation period. Similar pattern of alteration in serum glucose levels was observed by
Sharma et al., (2015) after injection of iohexol @ 600 mgI/ kg and urografin @ 600 mgI/kg body weight respectively in dogs. This increase in serum glucose level might have resulted due to stress created on the body by contrast agents. In contrary to our study,
Ganesh, (1995) reported significant (p<0.05) decrease in blood glucose level at 5 minutes after injection of both sodium diatrizoate (600 mg I/kg; 1000 mgI/kg) and iohexol (600 mg I/kg;1000 mgI/kg) contrast media with gradual increase to reached normal level in 30 minutes due to haemodiltuon caused by the fluid shift from extravascular to intravascular compartments. Following 1 hour of contrast administration, serum urea nitrogen and serum creatinine values showed a significant (p<0.05) increase followed by non-significant decrease till 24 hr of the observation period in both the groups (Table 2). To its contrary,
Sharma et al., (2015) documented transient non-significant increase in plasma urea nitrogen at 1 hr after iohexol administration @ 600 mg I/kg body weight due to combination of hypertonicity and direct chemical toxicity to the renal parenchyma. However, a significant (p<0.05) increase in plasma urea nitrogen was recorded at 1 hr interval after urografin administration @ 600 mg I/kg body weight. Similar pattern of variation in creatinine values was also reported by
Sharma et al., (2015) after iohexol @ 600 mg I/kg and urografin @ 600 mg I/kg administration in dogs. This might be due to direct effect of parenteral contrast administration leading to sudden and rapid deterioration in renal function that result in kidney failure to excrete nitrogenous waste products and regulating fluid and electrolyte homeostasis. Total serum protein showed non-significant marginal variations during the entire observation periodin both the groups. A non-significant increase of ALT, AST and ALP at 1 hr followed by very marginal decrease at 6 hr and 24 hr intervals after contrast administration in both the groups. The increase in ALT, AST and ALP level following 1 hr of contrast administration in both groups was probably as a result of detoxification in the liver. This finding was similar to
Gowtham, (2017) who reported non-significant variation in ALT, AST and ALP of male and female dogs after iohexol administration @ 800 mg I/kg body weight.
Urinalysis parameters
It was observed that the urine pH and specific gravity did not alter much and remained within normal physiological limits in both groups after administration of non-ionic and ionic contrast agents (Table 3). The above findings were in concurrence with those of
Sharma et al., (2015) following administration of iohexol and urografin 76% @ 600 mg I/kg respectively in dogs. Similarly,
Gowtham, (2017) reported variation in urine pH from 6.5 to7.5 in male dogs and 6.5 to 8.5 in female dogs while specific gravity between 1.005 to 1.015 in male dogs and 1 to 1.015 in female dogs after iohexol administration. In contrary to our study,
Ganesh, (1995) reported significant (p<0.05) decrease in urine specific gravity after 5 minutes of administration of both ionic and non-ionic contrast agent in dogs. Urine glucose was not evident in all the animals of group I and II during observation period at 0, 6 and 24 h after administration of iohexol @ 1100 mg I/ kg and urografin @ 1100 mg I/ kg body weight respectively. This finding suggests that both contrast agents did not caused any systemic effect on urine glucose profile.
Ganesh, (1995) observed that glucose was absent in urine in all the animals after administration of both sodium diatrizoate (600 mg I/kg; 1000 mgI/kg) and iohexol (600 mg I/kg; 1000 mgI/kg) contrast agent in dogs. Similar observation was reported by
Gowtham, (2017) after iohexol administration @ 800 mg I/kg body weight in both male and female dogs.
Physical examination of urine
Before administration of contrast agents, the colour of urine was yellow in all the dogs of both the groups except in 1 dog of group I where it was straw coloured (Table 4). Following 6 hr of contrast administration, there was no change in the urine colour in both the groups except in 1 dog of group II were it was straw coloured. At 24 h post contrast administration the urine colour was yellow in both the groups. Similarly,
Sharma et al., (2015) reported no change in urine colour in both iohexol and urografin 76% @ 600 mg I/kg group respectively in pre and post contrast urine sample in dogs.
Gowtham, (2017) documented similar pattern of change in urine colour after iohexol administration @ 800 mg I/kg body weight in both male and female dogs. The clarity of urine was clear in all the animals of group I and II. Similarly,
Gowtham, (2017) reported clear urine in all the dogs of both groups except in 1 male dog (group I) where it was slightly turbid after iohexol administration @ 800 mg I/kg body weight. Absence of sediments in urine was noticed in both group I and II.
Sharma et al., (2015) documented light deposition of sediments in both the groups following 1 hr of administration of iohexol and urografin76% @ 600 mg I/ kg body weight respectively in dogs. In accordance to the present study,
Gowtham, (2017) also reported absence sediments in urine in all the dogs of both groups except in 1 male dog (group I) where sediment was present after iohexol administration @ 800 mg I/kg body weight.
Adverse effects of contrast agents
No complication was observed after intravenous urography with non-ionic and ionic contrast agents (iohexol and urografin 76%) @ 1100 mg I/kg body weight in study animals. The contrast agents both non-ionic and ionic were well tolerated by dogs as well as no mortality was reported. The reason might be that before administration of contrast agents, chlorpheniramine maleate was given and both contrast agents were diluted with equal amount of 5% dextrose solution. The care was taken that the dose did not exceed 35 g of iodine. These findings were in accordance with
Ganesh, (1995) who observed no post radiographic mortality or morbidity in any of the animals regardless of drugs or dosage.
Koe and Alkan, (2002) also reported that dogs did not show any adverse reactions when the ionic (urografin 76%) and non-ionic (ultravist 300) contrast media were administered.