Modifications in Rat Testicular Morphology and Increases in IFN-γ Serum Levels by the Oral Administration of Subtoxic Doses of Mercuric Chloride

Figures & data

Daily Water Consumption and Hg Ingestion in Rats that Received Sublethal Doses of Mercuric Chloride by Oral Route^†

Months of treatment	Dose (μg/ml HgCl2)	Daily water consumption*ml/rat/day (x¯±SE)	Daily Hg ingestion** μg/rat/day (x¯±SE)
1	Control	49.95±0.85
	0.01	47.57±2.10	0.47±0.02
	0.05	48.62±0.95	2.43±0.05^a
	0.10	47.35±2.12	4.73±0.21^a,b
2	Control	44.24±0.92
	0.01	45.03±0.86	0.45±0.01
	0.05	44.54±0.64	2.22±0.03^a
	0.10	44.38±1.84	4.44±0.19^a,b
3	Control	43.50±0.85
	0.01	43.41±0.83	0.44±0.01
	0.05	45.28±0.87	2.26±0.01^a
	0.10	42.15±0.94	4.22±0.04^a,b

^†Results correspond to the mean and standard error from three different experiments.

*Consumption was calculated by dividing the amount of water ingested daily in each cage and the number of animals. Each cage contained 5 rats.

**Hg ingestion was calculated by multiplying the concentration of Hg supplied and the value obtained for daily water consumption per rat per day.

^aDifferences between the means of groups treated with 0.05 or 0.10 μg/ml of HgCl₂ and the group that received 0.01 μg/ml of HgCl₂ were statistically significant when compared by the non parametric Mann-Whitney U test; P < 0.001.

^bDifferences between the means of the group treated with 0.05 μg/ml of HgCl₂ and the group that received 0.10 μg/ml of HgCl₂ were statistically significant when compared by the non parametric Mann-Whitney U test; P< 0.001.

Body Weight and Relationships between the Male Reproductive Organ Weights and Body Weight in Rats that Received Sublethal Doses of Mercuric Chloride by Oral Route^†

Months of treatment	Dose (μg/ml HgCl2)	Body weight (g)	Testis weight (g)	Epididymis weight (g)	Testis/body weight (%)*	Epididymis/body weight (%)*
1	Control	424±25	1.74±0.11	0.59±0.03	0.41±0.020	0.13±0.007
	0.01	426±24	1.69±0.12	0.58±0.03	0.39±0.001	0.13±0.004
	0.05	410±28	1.65±0.10	0.50±0.01	0.40±0.020	0.12±0.004
	0.10	436±20	1.59±0.10	0.42±0.04	0.36±0.020	0.09±0.009^a,b
2	Control	503±20	1.79±0.10	0.77±0.04	0.35±0.020	0.12±0.009
	0.01	512±31	1.77±0.05	0.75±0.05	0.34±0.004	0.14±0.005
	0.05	476±25	1.78±0.06	0.78±0.05	0.35±0.010	0.15±0.009
	0.10	513±34	1.73±0.06	0.84±0.05	0.33±0.010	0.14±0.005
3	Control	524±34	1.65±0.07	0.56±0.01	0.31±0.010	0.11±0.004
	0.01	547±25	1.71±0.09	0.61±0.03	0.31±0.020	0.11±0.070
	0.05	490±36	1.91±0.14	0.62±0.06	0.39±0.030	0.14±0.010
	0.10	537±35	1.90±0.07	0.69±0.06	0.35±0.010	0.12±0.010

^†Results correspond to the mean and standard error from three different experiments.

^aDifferences between the means of the groups treated with 0.10 μg/ml of HgCl₂ and the control group was statistically significant when compared by the non parametric Kruskal-Wallis ANOVA; P< 0.005.

^bDifferences between the means of the group treated with 0.1 μg/ml of HgCl₂ and the group that received 0.01 μg/ml of HgCl₂ was statistically significant when compared by the non parametric Kruskal-Wallis ANOVA; P< 0.01.

Figure 1 Mercury concentrations in testis, epididymis or serum from rats that received sublethal doses of the metal by oral route. ▪ Control rats; ▴ Rats that received 0.01 μg/ml of Hg; • Rats that received 0.05 μg/ml of Hg; ♦ Rats that received 0.1 μg/ml of Hg. (A) Testis; (B) Epididymis; and (C) Serum.

Figure 2 Effects of the oral administration of Hg on testis morphology. (A) Microphotography of a tissue section from a control rat receiving deionized water (HE, 160X). (B) Cohesion loss in tubular cells (asterisks) and (C) Luminal obliteration (asterisks) in sections of rats that received 0.05 μg/ml of Hg for 1 month (HE, 250X). (D) Arrest at the spermatocyte stage (asterisks) and (E) Multinucleated giant cells in sections from rats that received 0.05 μg/ml of Hg for 2 months (HE, 100X, 400X). (F) Tubular atrophy in a section from a rat that received 0.1 μg/ml of Hg for 3 months (VG, 400X).

Severity of Lesions in Seminiferous Tubules from Rats that Received Mercuric Chloride by Oral Route

	Dose of Hg (μg/ml HgCl2)
Months of treatment	0.01	0.05	0.1
1	+^a	+	+
2	+	++	++
3	++	++	++

^aSymbols correspond to lesion severity: + Mild: Alterations in less than 10% of the tubules in tissue sections from one half or less of the total number of Hg-treated analyzed rats.

++ Moderate: Alterations in 20–50% of the tubules in tissue sections from more than one half of the total number of treated rats.

Figure 3 Effects of the oral administration of Hg on epididymis morphology. (A) Microphotography of a tissue section from a control rat that only received deionized water (VG, 250X). (B) Tissue section from a rat that received 0.01 μg/ml of Hg for 1 month, showing peritubular cell dissociation (arrows) (Iron H, 400X). (C) Tissue section from a rat that received 0.01 μg/ml of Hg for 3 months showing multinucleated giant cells (arrows) (Iron H, 400X).

Figure 4 Effects of the oral administration of Hg on the ultrastucture of testis. (A) Microphotography of a tissue section from a control rat that only received deionized water. N: Sertoli cell nucleus, Lys: lysosome, m: mitochondria, tw: tubular wall (6000X). (B) Damaged mitochondria (asterisks) (11500X), (C) Increased number of secondary lysosomes (arrows) and Golgi dilation (asterisks) in sections from rats that received 0.05 μg/ml of Hg for 3 months (5200X).

Figure 5 Leydig cell alteration in testis from rats that received Hg by oral route. (A) Microphotography of a tissue section from a control rat that only received deionized water. N: nucleus, m: mitochondria (arrows) (2950X). (B) Section from a rat treated with 0.05 μg/ml of Hg for 3 months showing peroxisomes (p), secondary lysosomes (ly) damaged mitochondria (m) and dilated endoplasmic reticulum (arrows) (6600X).

Figure 6 Effects of the oral administration of Hg on the ultrastucture of epididymis. (A) Myelinic figures (arrows) and (B) Crystal deposits in lysosomes of principal cells (arrows) from rats treated with 0.05 μg/ml of Hg for 3 months (6600X each).

Figure 7 Effects of the oral administration of sublethal doses of Hg on IFN-γ and IL-4 serum levels. Pooled results obtained from animals treated with mercury for different times.

Figure 8 Changes in IFN-γ serum levels in rats that received sublethal doses of Hg by oral route.